North Korea is getting around UN oil sanctions by transferring oil at sea, according to a top secret U.S. military report obtained by NBC News.
The transfers are taking place despite the presence of a U.S.-led coalition of forces monitoring the waters.
The U.S. military report found that the coalition's presence in the Korean peninsula has only forced North Korea to transfer oil further into the territorial waters of other countries, to avoid being spotted.
The report highlights the Trump administration's struggle to put economic pressure on North Korea as it tries to persuade the country to give up its nuclear weapons.
President Trump tweeted in response, "Many people have asked how we are doing in our negotiations with North Korea... We are doing just fine!"