diff --git a/src/pyqasm/maps/gates.py b/src/pyqasm/maps/gates.py
index 999c4828..f32a966d 100644
--- a/src/pyqasm/maps/gates.py
+++ b/src/pyqasm/maps/gates.py
@@ -1104,6 +1104,8 @@ def two_qubit_gate_op(
         "rz",
         "phaseshift",
         "p",
+        "u1",
+        "U1",
         "gpi",
         "gpi2",
         "xx",
diff --git a/src/pyqasm/visitor.py b/src/pyqasm/visitor.py
index 41fee124..8435e901 100644
--- a/src/pyqasm/visitor.py
+++ b/src/pyqasm/visitor.py
@@ -823,7 +823,7 @@ def _visit_basic_gate_operation(  # pylint: disable=too-many-locals
 
         if len(op_parameters) != actual_num_params:
             raise_qasm3_error(
-                f"Expected {op_qubit_count} parameter{'s' if op_qubit_count > 1 else ''}"
+                f"Expected {actual_num_params} parameter{'s' if actual_num_params != 1 else ''}"
                 f" for gate '{operation.name.name}', but got {len(op_parameters)}",
                 error_node=operation,
                 span=operation.span,