The U.S. announced on Wednesday its highest-level visit to Taiwan since it switched diplomatic recognition to China in 1979, a move Beijing blasted as a threat to “peace and stability”.

The visit, headed by health chief Alex Azar, comes as relations between the world’s two biggest powers plunge to historic lows.

“This marks... the first Cabinet member to visit in six years, and the highest level visit by a U.S. Cabinet official since 1979,” said Washington’s de facto Embassy, the American Institute in Taiwan, with no date yet given for the visit.

Washington remains the leading arms supplier to the island but has historically been cautious in holding official contacts with it.

Beijing views Taiwan as its own territory — vowing to one day seize it — and bristles at any moves by other countries to recognise or communicate with Taipei. “China firmly opposes official exchanges between the U.S. and Taiwan,” Wang Wenbin, a spokesman for China’s Foreign Ministry, said as he called for the visit to be cancelled.

Taiwan said Mr. Azar would meet President Tsai Ing-wen.