diff --git a/src/Common/src/Interop/Windows/BCrypt/Interop.NTSTATUS.cs b/src/Common/src/Interop/Windows/BCrypt/Interop.NTSTATUS.cs
index ec78838be805..49d674f3993b 100644
--- a/src/Common/src/Interop/Windows/BCrypt/Interop.NTSTATUS.cs
+++ b/src/Common/src/Interop/Windows/BCrypt/Interop.NTSTATUS.cs
@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Security.Cryptography;
 
 internal partial class Interop
 {
diff --git a/src/Common/src/System/OperationCanceledException.cs b/src/Common/src/System/OperationCanceledException.cs
new file mode 100644
index 000000000000..92d486129ca8
--- /dev/null
+++ b/src/Common/src/System/OperationCanceledException.cs
@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+
+namespace System
+{
+    internal class OperationCanceledException : Exception
+    {
+        public OperationCanceledException() 
+        {
+        }
+    }
+}
diff --git a/src/Common/src/System/Runtime/InteropServices/Marshal.Unix.cs b/src/Common/src/System/Runtime/InteropServices/Marshal.Unix.cs
new file mode 100644
index 000000000000..cd2294e37570
--- /dev/null
+++ b/src/Common/src/System/Runtime/InteropServices/Marshal.Unix.cs
@@ -0,0 +1,49 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Runtime.InteropServices
+{
+    // Stand-in type for low-level assemblies to obtain Win32 errors
+    internal static class Marshal
+    {
+        public static int GetLastWin32Error()
+        {
+            // issue: https://github.com/dotnet/corefx/issues/6778
+            // Need to define and implement this for Linux
+            return 0;
+        }
+        
+        unsafe public static String PtrToStringAnsi(IntPtr ptr)
+        {
+            if (IntPtr.Zero == ptr) 
+            {
+                return null;
+            }
+            
+            byte *pBytes = (byte *) ptr;
+            int length = 0; 
+            
+            while (*pBytes != 0)
+            {
+                pBytes++;
+                length++;
+            }
+            
+            if (length == 0)
+            {
+                return String.Empty;
+            }
+            
+            char [] chars = new char[length];
+            pBytes = (byte *) ptr;
+            
+            for (int i=0; i<length; i++)
+            {
+                chars[i] = (char) pBytes[i]; 
+            }
+            
+            return new string(chars);
+        }
+    }
+}
diff --git a/src/Common/src/System/Runtime/InteropServices/Marshal.cs b/src/Common/src/System/Runtime/InteropServices/Marshal.Win32.cs
similarity index 100%
rename from src/Common/src/System/Runtime/InteropServices/Marshal.cs
rename to src/Common/src/System/Runtime/InteropServices/Marshal.Win32.cs
diff --git a/src/System.Private.Uri/src/System.Private.Uri.builds b/src/System.Private.Uri/src/System.Private.Uri.builds
index 3ecec4d3c884..3d60aefc2284 100644
--- a/src/System.Private.Uri/src/System.Private.Uri.builds
+++ b/src/System.Private.Uri/src/System.Private.Uri.builds
@@ -18,6 +18,14 @@
       <OSGroup>Windows_NT</OSGroup>
       <TargetGroup>netcore50aot</TargetGroup>
     </Project>
+    <Project Include="System.Private.Uri.csproj">
+      <OSGroup>Windows_NT</OSGroup>
+      <TargetGroup>netstandard13aot</TargetGroup>
+    </Project>
+    <Project Include="System.Private.Uri.csproj">
+      <OSGroup>Linux</OSGroup>
+      <TargetGroup>netstandard13aot</TargetGroup>
+    </Project>
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.traversal.targets))\dir.traversal.targets" />
 </Project>
diff --git a/src/System.Private.Uri/src/System.Private.Uri.csproj b/src/System.Private.Uri/src/System.Private.Uri.csproj
index 7cbc640feb9e..3c5746607d9a 100644
--- a/src/System.Private.Uri/src/System.Private.Uri.csproj
+++ b/src/System.Private.Uri/src/System.Private.Uri.csproj
@@ -13,7 +13,7 @@
     <!-- Suppress warnings for type conflicts between SafeFileHandle in partial facade and mscorlib -->
     <NoWarn>0436</NoWarn>
     <PackageTargetFramework Condition="'$(PackageTargetFramework)'==''">netstandard1.0</PackageTargetFramework>
-    <SkipCommonResourcesIncludes Condition="'$(TargetGroup)'=='netcore50aot'">true</SkipCommonResourcesIncludes>
+    <SkipCommonResourcesIncludes Condition="'$(TargetGroup)'=='netcore50aot' Or '$(TargetGroup)'=='netstandard13aot'">true</SkipCommonResourcesIncludes>
     <NuGetTargetMoniker Condition="'$(TargetGroup)' == ''">.NETStandard,Version=v1.0</NuGetTargetMoniker>
   </PropertyGroup>
   <!-- Default configurations to help VS understand the configurations -->
@@ -27,8 +27,10 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Windows_Release|AnyCPU'"/>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Windows_netcore50aot_Debug|AnyCPU'"/>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Windows_netcore50aot_Release|AnyCPU'"/>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard13aot_Debug|AnyCPU'"/>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard13aot_Release|AnyCPU'"/>
   <ItemGroup>
-    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.cs" Condition="'$(TargetGroup)'!='netcore50aot'">
+    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.cs" Condition="'$(TargetGroup)'!='netcore50aot' And '$(TargetGroup)'!='netstandard13aot'">
       <Link>Common\System\Diagnostics\Debug.cs</Link>
     </Compile>
     <Compile Include="$(CommonPath)\System\Collections\Generic\LowLevelDictionary.cs">
@@ -77,7 +79,7 @@
     <Compile Include="$(CommonPath)\System\Globalization\IdnMapping.Windows.cs">
       <Link>Common\System\Globalization\IdnMapping.Windows.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.Windows.cs" Condition="'$(TargetGroup)'!='netcore50aot'">
+    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.Windows.cs" Condition="'$(TargetGroup)'!='netcore50aot' And '$(TargetGroup)'!='netstandard13aot'">
       <Link>Common\System\Diagnostics\Debug.Windows.cs</Link>
     </Compile>
     <Compile Include="$(CommonPath)\Interop\Windows\mincore\Interop.SetLastError.cs">
@@ -97,7 +99,7 @@
     <Compile Include="$(CommonPath)\System\Globalization\IdnMapping.Unix.cs">
       <Link>Common\System\Globalization\IdnMapping.Unix.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.Unix.cs">
+    <Compile Include="$(CommonPath)\System\Diagnostics\Debug.Unix.cs" Condition="'$(TargetGroup)'!='netcore50aot' And '$(TargetGroup)'!='netstandard13aot'">
       <Link>Common\System\Diagnostics\Debug.Unix.cs</Link>
     </Compile>
     <Compile Include="$(CommonPath)\Interop\Unix\Interop.Libraries.cs">
@@ -146,19 +148,28 @@
       <Link>Common\Microsoft\Win32\SafeHandles\SafeFileHandle.Unix.cs</Link>
     </Compile>
   </ItemGroup>
-  <ItemGroup Condition="'$(TargetGroup)'=='netcore50aot'">
+  <ItemGroup Condition="'$(TargetGroup)'=='netcore50aot' Or '$(TargetGroup)'=='netstandard13aot'">
     <TargetingPackReference Include="System.Private.CoreLib" />
     <EmbeddedResource Include="Resources\$(AssemblyName).rd.xml" />
-    <Compile Include="$(CommonPath)\System\SR.Core.cs">
+    <Compile Include="$(CommonPath)\System\SR.Core.cs" Condition="'$(TargetGroup)'=='netcore50aot'">
       <Link>Common\System\SR.Core.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)\System\SR.CoreRT.cs" Condition="'$(TargetGroup)'=='netstandard13aot'">
+      <Link>Common\System\SR.CoreRT.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)\System\Resources\NeutralResourcesLanguageAttribute.cs">
       <Link>Common\System\Resources\NeutralResourcesLanguageAttribute.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\System\Runtime\InteropServices\Marshal.cs">
-      <Link>Common\System\Runtime\InteropServices\Marshal.cs</Link>
+    <Compile Include="$(CommonPath)\System\Runtime\InteropServices\Marshal.Win32.cs"  Condition="'$(TargetsWindows)'=='true'">
+      <Link>Common\System\Runtime\InteropServices\Marshal.Win32.cs</Link>
+    </Compile>
+    <Compile Include="$(CommonPath)\System\Runtime\InteropServices\Marshal.Unix.cs"  Condition="'$(TargetsUnix)'=='true'">
+      <Link>Common\System\Runtime\InteropServices\Marshal.Unix.cs</Link>
+    </Compile>
+    <Compile Include="$(CommonPath)\System\OperationCanceledException.cs"  Condition="'$(TargetsUnix)'=='true'">
+      <Link>Common\System\System\OperationCanceledException.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)\Interop\Windows\mincore\Interop.GetLastError.cs">
+    <Compile Include="$(CommonPath)\Interop\Windows\mincore\Interop.GetLastError.cs" Condition="'$(TargetsWindows)'=='true'">
       <Link>Common\Interop\Windows\mincore\Interop.GetLastError.cs</Link>
     </Compile>
   </ItemGroup>
diff --git a/src/System.Private.Uri/src/project.json b/src/System.Private.Uri/src/project.json
index 5a5fdd2cb6d0..98bae6a026f2 100644
--- a/src/System.Private.Uri/src/project.json
+++ b/src/System.Private.Uri/src/project.json
@@ -12,6 +12,12 @@
       "dependencies": {
         "Microsoft.TargetingPack.Private.NETNative": "1.0.0-rc3-23908"
       }
+    },
+    "netstandard1.3": {
+      "imports": [ "netcore50" ],
+      "dependencies": {
+        "Microsoft.TargetingPack.Private.NETNative": "1.0.0-rc3-23908"
+      }
     }
   }
 }
diff --git a/src/System.Runtime.Extensions/src/System.Runtime.Extensions.builds b/src/System.Runtime.Extensions/src/System.Runtime.Extensions.builds
index 864ad172df27..e326e34db98b 100644
--- a/src/System.Runtime.Extensions/src/System.Runtime.Extensions.builds
+++ b/src/System.Runtime.Extensions/src/System.Runtime.Extensions.builds
@@ -21,6 +21,14 @@
       <OSGroup>Windows_NT</OSGroup>
       <TargetGroup>netcore50aot</TargetGroup>
     </Project>
+    <Project Include="System.Runtime.Extensions.csproj">
+      <OSGroup>Windows_NT</OSGroup>
+      <TargetGroup>netstandard13aot</TargetGroup>
+    </Project>
+    <Project Include="System.Runtime.Extensions.csproj">
+      <OSGroup>Linux</OSGroup>
+      <TargetGroup>netstandard13aot</TargetGroup>
+    </Project>
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.traversal.targets))\dir.traversal.targets" />
 </Project>
diff --git a/src/System.Runtime.Extensions/src/System.Runtime.Extensions.csproj b/src/System.Runtime.Extensions/src/System.Runtime.Extensions.csproj
index 21b5ef138858..7406046c9036 100644
--- a/src/System.Runtime.Extensions/src/System.Runtime.Extensions.csproj
+++ b/src/System.Runtime.Extensions/src/System.Runtime.Extensions.csproj
@@ -17,6 +17,9 @@
     <PackageTargetFramework Condition="'$(PackageTargetFramework)' == ''">netstandard1.3</PackageTargetFramework>
     <PackageTargetRuntime Condition="'$(TargetsWindows)' == 'true' And '$(TargetGroup)' != 'net46'">win7</PackageTargetRuntime >
     <PackageTargetRuntime Condition="'$(TargetsUnix)' == 'true'">unix</PackageTargetRuntime >
+    <PackageTargetRuntime Condition="'$(TargetsWindows)' == 'true' And '$(TargetGroup)' == 'netstandard13aot'">win-aot</PackageTargetRuntime >
+    <PackageTargetRuntime Condition="'$(TargetsUnix)' == 'true' And '$(TargetGroup)' == 'netstandard13aot'">unix-aot</PackageTargetRuntime >
+    <CoreClrOrCorRt Condition="'$(TargetGroup)' == '' Or '$(TargetGroup)' == 'netstandard13aot'">true</CoreClrOrCorRt>
   </PropertyGroup>
 
   <!-- Default configurations to help VS understand the configurations -->
@@ -32,8 +35,10 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'net46_Release|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Windows_netcore50aot_Debug|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Windows_netcore50aot_Release|AnyCPU'" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard13aot_Debug|AnyCPU'" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netstandard13aot_Release|AnyCPU'" />
 
-  <PropertyGroup Condition="'$(TargetGroup)' == 'netcore50aot'">
+  <PropertyGroup Condition="'$(TargetGroup)' == 'netcore50aot' Or '$(TargetGroup)' == 'netstandard13aot'">
     <SkipCommonResourcesIncludes>true</SkipCommonResourcesIncludes>
     <ExcludeAssemblyInfoPartialFile>true</ExcludeAssemblyInfoPartialFile>
   </PropertyGroup>
@@ -112,7 +117,7 @@
   </ItemGroup>
 
   <!-- WINDOWS: CoreCLR -->
-  <ItemGroup Condition=" '$(TargetsWindows)' == 'true' And '$(TargetGroup)' == ''">
+  <ItemGroup Condition=" '$(TargetsWindows)' == 'true' And '$(CoreClrOrCorRt)' == 'true'">
     <Compile Include="System\IO\Path.Win32.cs" />
     <Compile Include="$(CommonPath)\Interop\Windows\BCrypt\Interop.BCryptGenRandom.cs">
       <Link>Common\Interop\Windows\BCrypt\Interop.BCryptGenRandom.cs</Link>
@@ -162,15 +167,16 @@
   </ItemGroup>
 
   <!-- WINDOWS: .NET Native -->
-  <ItemGroup Condition="'$(TargetGroup)' == 'netcore50aot'">
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcore50aot' Or '$(TargetGroup)' == 'netstandard13aot'">
     <Compile Include="System\Random.cs" />
     <Compile Include="System\Net\Configuration\UnicodeDecodingConformance.cs" />
     <Compile Include="System\Net\Configuration\UnicodeEncodingConformance.cs" />
     <Compile Include="System\IO\LowLevelTextWriter.cs" />
     <Compile Include="System\IO\LowLevelStringWriter.cs" />
-    <Compile Include="System\IO\Path.WinRT.cs" />
-    <Compile Include="$(CommonPath)\Interop\Windows\mincore\Interop.GetLastError.cs" />
-    <Compile Include="$(CommonPath)\System\SR.Core.cs" />
+    <Compile Include="System\IO\Path.WinRT.cs" Condition="'$(TargetGroup)' == 'netcore50aot' And '$(TargetsWindows)'=='true'"/>
+    <Compile Include="$(CommonPath)\Interop\Windows\mincore\Interop.GetLastError.cs" Condition="'$(TargetsWindows)'=='true'"/>
+    <Compile Include="$(CommonPath)\System\SR.Core.cs" Condition="'$(TargetGroup)' == 'netcore50aot' And '$(TargetsWindows)'=='true'"/>
+    <Compile Include="$(CommonPath)\System\SR.CoreRT.cs" Condition="'$(TargetGroup)' == 'netstandard13aot' Or '$(TargetsUnix)'=='true'"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetGroup)' == ''">
@@ -183,14 +189,18 @@
     <TargetingPackReference Include="System" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetGroup)' == 'netcore50aot'">
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcore50aot' Or '$(TargetGroup)' == 'netstandard13aot'">
     <TargetingPackReference Include="System.Private.CoreLib" />
     <TargetingPackReference Include="System.Private.CoreLib.InteropServices" />
     <TargetingPackReference Include="System.Private.Interop" />
     <TargetingPackReference Include="System.Private.Threading" />
-    <ProjectReference Include="$(SourceDir)/mscorlib.WinRT-Facade/mscorlib.WinRT-Facade.csproj" />
-    <ProjectReference Include="..\..\System.Runtime\src\System.Runtime.csproj" />
+    <ProjectReference Include="$(SourceDir)/mscorlib.WinRT-Facade/mscorlib.WinRT-Facade.csproj" Condition="'$(TargetGroup)' == 'netcore50aot'"/>
+    <ProjectReference Include="..\..\System.Runtime\src\System.Runtime.csproj" >
+        <TargetGroup>netcore50aot</TargetGroup>
+    </ProjectReference>
     <ProjectReference Include="..\..\System.Private.Uri\src\System.Private.Uri.csproj" />
+    <ValidateIgnoreReference Include="@(TargetingPackReference)" Condition="'$(TargetGroup)' == 'netstandard13aot'"/>
+    <ValidateIgnoreReference Include="System.Private.Uri" Condition="'$(TargetGroup)' == 'netstandard13aot'"/>
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/System.Runtime.Extensions/src/project.json b/src/System.Runtime.Extensions/src/project.json
index 0a487a76d1c4..0427ac355806 100644
--- a/src/System.Runtime.Extensions/src/project.json
+++ b/src/System.Runtime.Extensions/src/project.json
@@ -15,6 +15,12 @@
         "Microsoft.TargetingPack.Private.NETNative": "1.0.0-rc3-23908",
         "Microsoft.TargetingPack.Private.WinRT": "1.0.1"
       }
+    },
+    "netstandard1.3": {
+      "imports": [ "netcore50" ],
+      "dependencies": {
+        "Microsoft.TargetingPack.Private.NETNative": "1.0.0-rc3-23908"
+      }
     }
   }
 }