WASHINGTON – Two long-range U.S. bombers have conducted what Pentagon officials described Tuesday as a routine training mission through airspace recently claimed by China as its “air defense identification zone.”

The Chinese government said Saturday that it had the right to identify, monitor and possibly take military action against aircraft that enter the area, which includes sea and islands also claimed by Japan. The claim threatens to escalate an already tense dispute over some of the maritime territory.

U.S. officials said the pair of B-52s carried out a mission that had been planned long in advance of the Chinese announcement last weekend, and that the U.S. military would continue to assert its right to fly through what it regards as international airspace. Pentagon officials said the two bombers made a round-trip flight from Guam, passing through a zone that covers sea and islands that are the subject of a sovereignty dispute between Japan and China.

Officials said there had been no Chinese response to the bomber run.

The Obama administration has become increasingly worried by the tense standoff over the islands, which could drag the United States into a conflict. By treaty, the United States is obligated to defend Japan if it is attacked.

The islands, called the Senkaku in Japan and the Diaoyu in China, are currently administered by the Japanese, who consider the airspace above the islands to be theirs as well.

On Tuesday, Josh Earnest, a deputy White House spokesman, reiterated the administration’s view that the Chinese announcement was “unnecessarily inflammatory” and had a “destabilizing impact on the region.”

Within hours of the Chinese announcement that it had declared what Beijing termed an “East China Sea air defense identification zone,” U.S. Defense Secretary Chuck Hagel issued a statement expressing deep concern over the action.

“We view this development as a destabilizing attempt to alter the status quo in the region,” Hagel said. “This unilateral action increases the risk of misunderstanding and miscalculations.” Hagel noted, “this announcement by the People’s Republic of China will not in any way change how the United States conducts military operations in the region.”