diff --git a/DependencyInjection/Configuration.php b/DependencyInjection/Configuration.php
index 250b78b..2ff3b59 100644
--- a/DependencyInjection/Configuration.php
+++ b/DependencyInjection/Configuration.php
@@ -16,7 +16,7 @@
 
 class Configuration implements ConfigurationInterface
 {
-    const SERVICE_CALLABLE_NOTATION_REGEX = '/^@(?<service_id>[a-z0-9\._]+)(?:\:(?<method>[a-zA-Z_\x7f-\xff][a-z0-9_\x7f-\xff]*))?$/i';
+    const SERVICE_CALLABLE_NOTATION_REGEX = '/^@(?<service_id>[a-z0-9\._\\\]+)(?:\:(?<method>[a-zA-Z_\x7f-\xff][a-z0-9_\x7f-\xff]*))?$/iu';
     const PHP_CALLABLE_NOTATION_REGEX = '/^(?<function>(?:\\\\?[a-z_\x7f-\xff][a-z0-9_\x7f-\xff]*)+)(?:\:\:(?<method>[a-z_\x7f-\xff][a-z0-9_\x7f-\xff]*))?$/i';
 
     public function getConfigTreeBuilder()
diff --git a/Tests/DependencyInjection/OverblogDataLoaderExtensionTest.php b/Tests/DependencyInjection/OverblogDataLoaderExtensionTest.php
index e26c0b1..d2d0ac8 100644
--- a/Tests/DependencyInjection/OverblogDataLoaderExtensionTest.php
+++ b/Tests/DependencyInjection/OverblogDataLoaderExtensionTest.php
@@ -11,6 +11,7 @@
 
 namespace Overblog\DataLoaderBundle\Tests\DependencyInjection;
 
+use Overblog\DataLoaderBundle\DependencyInjection\Configuration;
 use Overblog\DataLoaderBundle\DependencyInjection\OverblogDataLoaderExtension;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\DependencyInjection\Alias;
@@ -41,6 +42,22 @@ public function tearDown()
         unset($this->container, $this->extension);
     }
 
+    public function testValidServiceCallableNodeValue()
+    {
+        $validValues = ['@app.user:getUsers', '@App\\Loader\\User:all'];
+        foreach ($validValues as $validValue) {
+            $this->assertRegExp(Configuration::SERVICE_CALLABLE_NOTATION_REGEX, $validValue);
+        }
+    }
+
+    public function testValidPhpCallableNodeValue()
+    {
+        $validValues = ['Image\\Loader::get', 'Post::getPosts'];
+        foreach ($validValues as $validValue) {
+            $this->assertRegExp(Configuration::PHP_CALLABLE_NOTATION_REGEX, $validValue);
+        }
+    }
+
     public function testUsersDataLoaderConfig()
     {
         $this->loadValidConfig();