diff --git a/vppcfg/config/interface.py b/vppcfg/config/interface.py
index 4d0e418..30cfef0 100644
--- a/vppcfg/config/interface.py
+++ b/vppcfg/config/interface.py
@@ -530,7 +530,7 @@ def validate_interfaces(yaml):
                     f"interface {ifname} unnumbered target {target} cannot be in L2 mode"
                 )
                 result = False
-            if is_unnumbered(yaml, target):
+            if is_unnumbered(yaml, target) or loopback.is_unnumbered(yaml, target):
                 msgs.append(
                     f"interface {ifname} unnumbered target {target} cannot also be unnumbered"
                 )
@@ -692,7 +692,7 @@ def validate_interfaces(yaml):
                             f"sub-interface {sub_ifname} unnumbered target {target} cannot be in L2 mode"
                         )
                         result = False
-                    if is_unnumbered(yaml, target):
+                    if is_unnumbered(yaml, target) or loopback.is_unnumbered(yaml, target):
                         msgs.append(
                             f"sub-interface {sub_ifname} unnumbered target {target} cannot also be unnumbered"
                         )
diff --git a/vppcfg/config/loopback.py b/vppcfg/config/loopback.py
index 4bea0ff..71cab0d 100644
--- a/vppcfg/config/loopback.py
+++ b/vppcfg/config/loopback.py
@@ -113,7 +113,7 @@ def validate_loopbacks(yaml):
                     f"loopback {ifname} unnumbered target {target} does not exist"
                 )
                 result = False
-            if is_unnumbered(yaml, target):
+            if is_unnumbered(yaml, target) or interface.is_unnumbered(yaml, target):
                 msgs.append(
                     f"loopback {ifname} unnumbered target {target} cannot also be unnumbered"
                 )
diff --git a/vppcfg/unittest/yaml/error-unnumbered2.yaml b/vppcfg/unittest/yaml/error-unnumbered2.yaml
index d17e20c..f7b5905 100644
--- a/vppcfg/unittest/yaml/error-unnumbered2.yaml
+++ b/vppcfg/unittest/yaml/error-unnumbered2.yaml
@@ -6,7 +6,7 @@ test:
       - "(sub-)?interface .* unnumbered target .* cannot also be unnumbered"
       - "loopback .* unnumbered target cannot point to itself"
       - "loopback .* unnumbered target .* cannot also be unnumbered"
-    count: 12
+    count: 16
 ---
 loopbacks:
   loop0:
@@ -15,6 +15,10 @@ loopbacks:
     unnumbered: loop0
   loop2:
     unnumbered: loop2
+  loop3:
+    unnumbered: GigabitEthernet2/0/0
+  loop4:
+    unnumbered: GigabitEthernet1/0/0.100
 
 interfaces:
   GigabitEthernet1/0/0:
@@ -31,6 +35,9 @@ interfaces:
   GigabitEthernet2/0/1:
     description: "Cannot point to Gi2/0/0, as that interface is itself unnumbered"
     unnumbered: GigabitEthernet2/0/0
+  GigabitEthernet2/0/2:
+    description: "Cannot point to Gi2/0/0, as that interface is itself unnumbered"
+    unnumbered: loop0
 
   GigabitEthernet3/0/0:
     sub-interfaces:
@@ -40,3 +47,6 @@ interfaces:
       101:
         description: "Cannot point to Gi3/0/0.100, as that interface is itself unnumbered"
         unnumbered: GigabitEthernet3/0/0.100
+      102:
+        description: "Cannot point to Gi3/0/0.100, as that interface is itself unnumbered"
+        unnumbered: loop0