The US military says it has sent two Navy warships through the Taiwan Strait, with the Pentagon increasing the frequency of movement through the strategic waterway despite Chinese opposition.
Sunday's voyage risks further raising tensions with China but will likely be viewed by self-ruled Taiwan as a sign of support from the Trump administration.
Taiwan is one of a growing number of flashpoints in the US-China relationship, which also include a trade war, sanctions and China's increasingly muscular military posture in the South China Sea, where the United States also conducts freedom-of-navigation patrols.
The two destroyers were identified as the William P. Lawrence and Stethem. The 180km-wide Taiwan Strait separates Taiwan from China.
"The ships' transit through the Taiwan Strait demonstrates the US commitment to a free and open Indo-Pacific," the US Pacific Fleet said in a statement.
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The United States has no formal ties with Taiwan but is bound by law to help defend the island nation and is its main source of arms. The Pentagon says Washington has sold Taipei more than $US15 billion in weaponry since 2010.
China has been ramping up pressure to assert its sovereignty over the island, which it considers a wayward province of "one China".
China said a recent Taiwan Strait passage by a French warship, first reported by Reuters on Wednesday, was "illegal."
Beijing's concerns about Taiwan are likely to factor strongly into this year's Chinese defence budget, following a stern New Year's speech from President Xi Jinping threatening to attack Taiwan should it not accept Chinese rule.
