The Trump administration says it has seized a North Korean cargo ship that U.S. officials say was used to transport coal in violation of international sanctions.

The Justice Department said the ship, the Wise Honest, is one of North Korea's largest bulk carriers and for several years had been used to deliver Russian coal to North Korea.

Payments for maintenance and equipment for the vessel were made in American dollars through unwitting U.S. banks, a violation of sanctions that bar North Korean citizens or entities from the U.S. financial system.

Officials say North Korea sought to conceal the vessel's purpose by listing in shipping documentation different countries for its nationality and the origin of the coal.

"This sanctions-busting ship is now out of service," said Assistant Attorney General John Demers, the Justice Department's top national security official.

According to a civil complaint filed Thursday in federal court in Manhattan, the ship was intercepted and seized by Indonesian authorities on April 2, 2018. At the time, it was about 2,800 miles south of Nampo, North Korea, where it had been photographed a month earlier. The complaint says that after taking the load of coal, the ship sailed south with it toward Indonesia.

The vessel has since been taken into custody by the U.S.

The announcement was made at a time of tension between the two countries.

It came hours after North Korea fired two suspected short-range missiles in its second weapons launch in five days.

The launch is a possible sign that nuclear disarmament talks with the U.S. could be in danger.

Trump told reporters at the White House on Thursday that "we're looking" at the missile launch situation "very seriously right now."

He said the weapons were smaller, short-range missiles, but added: "Nobody's happy about it."

In another sign of diminishing relations, the Pentagon also said Wednesday that it has suspended its efforts to arrange negotiations on recovering additional remains of U.S. service members killed in the North during the Korean War.

Trump, who has met with North Korean leader Kim Jong Un twice now, said: "I don't think they're ready to negotiate."