“A pair of American B-52 bombers flew over a disputed island chain in the East China Sea” on Monday, according to The Wall Street Journal, “in a direct challenge to China and its establishment of an expanded air-defense zone.”

Citing “U.S. officials” as its sources, the Journal adds that Chinese authorities were not told in advance of the planes’ flights.

Several other news outlets, including The New York Times, are also reporting the news. NPR correspondents are working their sources.

As we reported Sunday, “in a move that angered Japan, China expanded its air defense zone to include a group of uninhabited islands claimed by both countries. The Chinese government released a map and coordinates on Saturday that show the zone covers most of the East China Sea, including the islands.”

Both Japan and the U.S. made clear they wouldn’t respect the new zone. “Washington, which has hundreds of military aircraft based in the region, says it has zero intention of complying,” The Associated Press wrote early Tuesday. “Japan likewise has called the zone invalid, unenforceable and dangerous, while Taiwan and South Korea, both close to the U.S., also rejected it.”

More: Reports: U.S. Flies B-52s Through China’s Proclaimed Airspace : The Two-Way : NPR