diff --git a/src/Rules/MinLength.php b/src/Rules/MinLength.php
index 3ed0b40..6ecc5b5 100755
--- a/src/Rules/MinLength.php
+++ b/src/Rules/MinLength.php
@@ -63,7 +63,7 @@ public function validate(): bool
                 'Rule "min_length": the rule value is mandatory'
             );
         }
-        if (!is_int($this->ruleValues[0])) {
+        if (!\is_numeric($this->ruleValues[0])) {
             throw ValidatorException::noIntegerValue($this->ruleValues[0]);
         }
 
diff --git a/tests/MinLengthTest.php b/tests/MinLengthTest.php
index db3811f..bdea502 100755
--- a/tests/MinLengthTest.php
+++ b/tests/MinLengthTest.php
@@ -82,14 +82,12 @@ public function testValidateNull(): void
     }
 
     /**
-     * An Empty String ('') value should pass validation (ignored field).
-     *
-     * @return void
+     * A numeric string, e.g. '10', should be accepted as rule value.
      */
-    // public function testValidateEmptyString(): void
-    // {
-    //     $this->assertTrue($this->validate('', [5]));
-    // }
+    public function testValidateNumericString(): void
+    {
+        $this->assertFalse($this->validate('text with 23 characters', ['30']));
+    }
 
     /**
      * The String ('text with 23 characters') value should violate the rule with min length of 30 characters.