Days after China asserted greater military control over a swath of the East China Sea to bolster claims to a cluster of disputed islands, the U.S. defied the move Tuesday as it flew two B-52 bombers through the area.

The U.S. said what it described as a training mission was not flown to respond to China’s latest military maneuver, yet the dramatic flights made clear that the U.S. will not recognize the new territorial claims that Beijing laid out over the weekend.

The two unarmed U.S. B-52 bombers took off from their home base in Guam and flew through China’s newly designated air defense zone, then returned to base, U.S. officials said.

The bombers were in the zone for less than an hour, thundering across the Pacific skies during midday there, the officials said, adding that the aircraft encountered no problems.

While the U.S. insisted the training mission was long-planned, it came just days after China issued a map and a new set of rules governing the zone, which includes a cluster of islands that are controlled by Japan but claimed by Beijing.

U.S. officials would not publicly acknowledge the flights on Tuesday, but State Department spokeswoman Jen Psaki said China’s move appeared to be an attempt to change the status quo in the East China Sea.

"This will raise regional tensions and increase the risk of miscalculation, confrontation and accidents," she told reporters.

China said Saturday that all aircraft entering the new air defense zone must notify Chinese authorities and are subject to emergency military measures if they do not identify themselves or obey Beijings orders.

U.S. officials, however, said they have received no reaction to the bomber flights from the Chinese.

The bomber mission underscores Washington’s immediate rejection of Chinas new rules. The U.S., which has hundreds of military aircraft based in the region, has said it has zero intention of complying.

Japan likewise has called the zone invalid, unenforceable and dangerous, while Taiwan and South Korea, both close to the U.S., also rejected it.

White House spokesman Josh Earnest would not specifically comment Tuesday on the military flights. "It continues to be our view that the policy announced by the Chinese over weekend is unnecessarily inflammatory and has a destabilizing impact on the region," he told reporters traveling with Obama in Los Angeles.

The U.S. mission took place between about midnight Monday and 3 a.m. EST, said the officials, who requested anonymity because they were not authorized to speak by name about the flights.

The flights were first reported by The Wall Street Journal.Chinas move to further assert its territorial claims over the islands is not expected to immediately spark confrontations with foreign aircraft.

Yet it fits a pattern of putting teeth behind China’s claims and could potentially lead to dangerous encounters depending on how vigorously China enforces it — and how cautious it is when intercepting aircraft from Japan, the U.S. and other countries.

While enforcement is expected to start slowly, Beijing has a record of playing the long game, and analysts say they anticipate a gradual scaling-up of activity.

The declaration seems to have flopped as a foreign policy gambit. Analysts say Beijing may have miscalculated the forcefulness and speed with which its neighbors rejected its demands.

At least in the short term, the move undermines Beijings drive for regional influence, said Bonnie Glaser, an Asia expert at the Center for Strategic and International Studies in Washington