WASHINGTON — The United States has seized a North Korean shipping vessel that was violating American law and international sanctions, the Justice Department announced Thursday, a move certain to escalate tensions already on the rise because of recent North Korean weapons tests.

Prosecutors said the carrier ship, the Wise Honest, was being used to export North Korean coal, a critical sector of the North’s economy that the United States and the United Nations have aggressively imposed sanctions on in an effort to force Pyongyang to end its nuclear weapons program. The ship was also being used to import heavy machinery.

It was the first time the United States has seized a North Korean cargo vessel for international sanctions violations, the Justice Department said. Officials said the seizure is part of a broad plan to enforce the international sanctions and ultimately pressure North Korea to dismantle its nuclear program.

“This sanctions-busting ship is now out of service,” said John C. Demers, the head of the Justice Department’s national security division. The complaint was filed in Federal District Court in Manhattan on Thursday by the United States attorney’s office for the Southern District of New York.