Photo/Illutration A Chinese Coast Guard cutter, background, tails a Vietnamese boat in waters near the Paracel Islands in the South China Sea. (Asahi Shimbun file photo)

BEIJING--A British frigate was sailing through the sensitive Taiwan Strait on Monday en route to Vietnam, according to an official tweet from the vessel, in a move likely to anger Beijing amid heightened tensions between China and Taiwan.

China claims Taiwan as its own territory and has stepped up military and political pressure to force the democratically ruled island to accept Chinese sovereignty.

While U.S. warships pass through the strait on an almost monthly basis, despite Chinese opposition, U.S. allies have generally been reluctant to follow suit.

Taiwan Defense Minister Chiu Kuo-cheng did not comment directly when asked about the British warship, saying he did not know what missions foreign ships in the Taiwan Strait were carrying out.

“When they pass through the Taiwan Strait our nation’s military will have a grasp of the situation, but will not interfere,” he told reporters in Taipei, adding they keep a close watch on all movements near Taiwan.

Britain’s HMS Richmond had been deployed in the East China Sea taking part in United Nations sanctions enforcement operations against North Korea.

China has been ramping up its exercises around Taiwan and flies air force aircraft almost daily into the southwestern part of Taiwan’s air defense zone.