The Pentagon announced Tuesday that it had defied Beijing by flying two warplanes over the East China Sea on a training exercise, ignoring a recent edict from China that it be informed in advance of any such flights in the region.

U.S. military officials said they deployed two unarmed B-52 bombers late Monday over a small island chain that China and Japan both claim as their territory. Lt. Col. Tom Crosson, a military spokesman, described the flights as “uneventful” and said they were part of a previously scheduled training mission. He said there was “no contact, no reaction from China.”

Pentagon officials said the flights were intended to send a clear message to Beijing that Washington would not permit China to restrict freedom of movement in international airspace or waterways. In addition to its dispute with Japan, China is engaged in spats with other U.S. allies in Asia, fueling political tension as all sides vie for strategically important territory.

On Saturday, China declared that it had imposed an “air defense identification zone” over part of the East China Sea and the uninhabited islands, known as the Senkaku in Japan and Diaoyu in China. The Chinese Defense Ministry warned that any noncommercial aircraft entering the zone would need to submit flight plans in advance and maintain radio contact with Chinese authorities or else face unspecified “defensive emergency measures.”

Japan and the United States immediately protested the move. The Pentagon, which frequently conducts naval and air exercises in the East China Sea, said Saturday that it had no intention of bowing to China’s demands, calling them a “destabilizing attempt to alter the status quo in the region.”

(The Washington Post)

Less than 48 hours later, the long-range B-52 bombers took off from a military base in Guam and spent about an hour in the disputed zone before returning to the U.S. territory in the Pacific.

On Tuesday, the White House criticized China’s imposition of the air defense identification zone but urged Beijing to address territorial conflicts diplomatically instead of militarily.

“We believe that inflammatory rhetoric and inflammatory policy pronouncements like those made by the Chinese over the weekend are counterproductive, and we believe that those differences of opinion can and should be resolved diplomatically,” White House spokesman Josh Earnest told reporters. “It’s in the interest of all of the parties in the region to do that.”

China said Wednesday morning that it had identified and observed the U.S. planes throughout their journey through the zone, as it will for all aircraft traveling through the area.

“What we need to emphasize is that China will identify all activities of all aircraft in the East China Sea Air Defense Identification Zone,” Defense Ministry spokesman Geng Yansheng said in a statement. “China has the ability to take effective management and control of the relevant airspace.”

Experts in Beijing expressed concern about a further escalation of tension and said military conflict was possible.

“It’s a clear provocation,” said Sun Zhe, director of the Center for U.S.-China Relations at Tsinghua University in Beijing. The possibility of China challenging the U.S. air defense zone could not be ruled out in the future, he said.

“This announcement and quick U.S. response have clarified the U.S.’ siding with Japan much more than the past,” said Mathieu Duchatel of the Stockholm International Peace Institute in Beijing. “So there is some degree of miscalculation” by China.

Analysts in Washington said they did not expect Beijing to respond militarily but predicted that tension over the island chain would continue to be a potential flash point.

“The Chinese aren’t going to back off. We’re not going to back off,” said Patrick Cronin, an Asia analyst at the Center for a New American Security, a Washington think tank that consults closely with the Obama administration. “So right now, the trajectory is that there’s going to be some kind of mishap in the next couple of years.”

Japanese Chief Cabinet Secretary Yoshihide Suga declined Wednesday to speak specifically about the flight of the B-52s but said the United States and Japan had been “closely collaborating” concerning China’s new air defense zone.

Secretary of State John F. Kerry spoke by phone with Japan’s foreign minister, Fumio Kishida, on Tuesday, a Foreign Ministry spokesman said. Kerry told Kishida that China’s new edict represented a “dangerous act” taken unilaterally, the spokesman said.

Separately, Japan’s two biggest commercial carriers said they would not report flight plans for planes traveling through China’s air defense zone. Those carriers, Japan Airlines and All Nippon Airways, had initially said they would comply with the Chinese edict, but they reversed their stance at the request of the Japanese government, Suga said.

The United States has a mutual defense treaty with Japan and has pledged to aid Tokyo if a military conflict over the islands erupts. The territorial dispute has escalated since last year, when Tokyo purchased three of the islands from a private landowner. Subsequently, both countries have sent patrol ships into the contested waters to stake their ownership and spy on each other.

Numerous countries, including the United States and Japan, have their own air defense identification zones. The zones are established to help nations monitor aircraft nearing their territories, but in this case the zones of Japan and China overlap.

The airspace fight threatens to cloud a planned trip by Vice President Biden to Beijing next week. Biden is scheduled to meet with Chinese President Xi Jinping, in between visits to Japan and South Korea.  

It also could undermine long-standing efforts by the Pentagon to forge a more cooperative relationship with the People’s Liberation Army (PLA), which is investing heavily in naval and air forces as it seeks to extend its influence in the region.

Although the two countries view each other as rivals in security matters, U.S. military officials say it is vital that communication lines remain open to avoid hostile encounters that could mushroom into something worse. Over the past two years, both sides have agreed to an unprecedented number of visits and exchanges by senior military officials, raising hopes in the Pentagon that it could at least do business with the PLA, even if they don’t always agree.

In September, for instance, Gen. Mark A. Welsh III became the first chief of staff of the Air Force to visit China in 15 years. The chiefs of the Army, Navy and Marine Corps are all scheduled to go to Beijing next year.

“What their motives are, ambitions are, I wouldn’t even pretend to guess those,” Welsh said of his Chinese military counterparts at a breakfast with reporters this month. “But anything that helps us communicate in a more meaningful way is good. Just to avoid the tensions that are going to occur as we, I hate to use the term ‘collide,’ but as we interact or come close to each other militarily more and more and more in that part of the world.”

Simon Denyer, Li Qi, Liu Liu and Guo Chen in Beijing and Chico Harlan in Seoul contributed to this report.