The Trump administration on Tuesday threatened to cutoff from the U.S. financial system Chinese and Russian companies helping North Korea smuggle coal overseas to circumvent international sanctions on Pyongyang’s nuclear activities.

Marshall Billingslea, the Treasury Department’s assistant secretary for terrorist financing, provided Congress with intelligence images mapping North Korea’s illicit shipping networks used to mask the origin of exported coal to China and Russia.

The images appear to expose China and Russia’s covert hand in undermining international pressure on the Kim Jong Un regime to give up its nuclear ambitions, despite the two nations voting publicly on several occasions at the United Nations Security Council to strengthen sanctions.

“North Korea has been living under United Nations sanctions for over a decade and it has nevertheless made significant strides toward its goal of building a nuclear tipped ICBM,” Billingslea testified before the House Foreign Affairs Committee, referring to the regime’s pursuit of an intercontinental ballistic missile capable of reaching the United States mainland.