The top American diplomat for Asia has vowed that the U.S. military will continue to operate in the Taiwan Strait, saying Thursday that any moves by China to prevent the operations would be “deeply destabilizing,” just a day after Beijing’s ambassador to Washington warned against such operations.

“The White House and the Pentagon have made clear that the United States will continue to fly, sail and operate anywhere that international law allows — and that includes our continuance of routine transits through the Taiwan Strait,” said Daniel Kritenbrink, the U.S. assistant secretary of state for the Bureau of East Asian and Pacific Affairs.

“Our transits through the strait are routine and long-standing and they will continue,” he told reporters. “It would be deeply destabilizing and irresponsible if China were to try to take steps designed to control or restrict the ability of the United States or others to transit the strait, or were it to take steps that would threaten the ability of shipping and commerce to go through the strait.”