The U.S. is preparing its USS John McCain, a state-of-the-art Aegis-guided missile destroyer, for a possible interception of a North Korean-flagged ship suspected of transporting weapons materials in violation of a U.N. Security Council resolution passed June 12th.

CNN and other U.S. news agencies say the U.S. military is tracking the “Kang Nam” vessel, which left North Korea Wednesday and is moving southward along the Chinese coast. The ship has, in the past, been a repeat violator of international weapons transport restrictions.

If the order to intercept is given, the USS John McCain will first approach the North Korean ship to ask permission to board, an act permitted by the U.N. Security Council resolution.

If the North refuses, the U.S. will report the matter to the U.N. and the ship will be shadowed to its port. The port authorities would then conduct a search for any illegal weapons or related materials.

North Korea has said that any search of its ships would be considered an act of war and would be accompanied by a massive retaliation on behalf of Pyongyang.