TOKYO Two U.S bombers flew over the disputed South China Sea, the U.S. Air Force said in a statement on Friday, asserting the right to treat the region as international territory, despite China’s territorial claims in the busy waterway.

Before their flight on Thursday, the two B-1Bs trained with Japanese jet fighters in the neighboring East China Sea, the first time the two forces have ever conducted night-time drills.

That U.S. military activity came amid heightened tension in the region after North Korea claimed it has developed a long range missile that could threaten the United States.

The U.S. wants China to do more to pressure Pyongyang to halt its research into missiles and nuclear bombs.

(Reporting by Tim Kelly; Editing by Clarence Fernandez)