“A pair of American B-52 bombers flew over a disputed island chain in the East China Sea without informing Beijing, U.S. officials said, in a direct challenge to China and its establishment of an expanded air defense zone,” the Wall Street Journal reports.

“The planes flew out of Guam and entered the new Chinese Air Defense Identification Zone at about 7 p.m. ET Monday, according to a U.S. official. Over the weekend, Beijing said it was expanding its Air Defense Identification Zone to include the island chain, which is claimed by both Beijing and Tokyo but administered by Japan.”

“The islands, the source of growing friction in the region, are known as the Diaoyu Islands in China and Senkaku Islands in Japan. Defense officials earlier had promised that the U.S. would challenge the zone and would not comply with Chinese requirements to file a flight plan, radio frequency or transponder information.”