Two U.S. Air Force B-1B bombers flew a 10-hour mission Thursday from Guam through the disputed South China Sea in an operation with a Navy guided-missile destroyer, the U.S. military said.

The joint training, organized under the U.S. Pacific Command's "continuous bomber presence" program in Guam, was aimed at bolstering interoperability between the Navy and Air Force "by refining joint tactics, techniques and procedures while simultaneously strengthening their ability to seamlessly integrate their operations," according to a statement by the U.S. Pacific Air Forces.

It did not say where exactly the flights took place, and did not refer to the exercise as a "freedom of navigation operation" that challenges what the U.S. calls Beijing's excessive claims to the South China Sea.