The US has approved a possible $620m (£492.5m) upgrade package for Patriot surface-to-air missiles to Taiwan, the State Department said, the latest purchase from the US to deal with a rising threat from China.
The US, like most countries, has no official diplomatic ties with Taiwan, but is bound by law to provide the democratic island with the means to defend itself.
China, which claims the democratically-ruled island as its own territory, routinely denounces US arms sales to Taiwan.