Washington's top diplomat in Taipei said on Friday the U.S. is committed to bolstering Taiwan's ability to defend itself.
Sandra Oudkirk, who heads the de-facto U.S. embassy in Taiwan, said that in the first news briefing since she took up post in July.
"The United States has a commitment to help Taiwan provide for its self-defence, and that's part of the Taiwan Relations Act, it's a commitment that we take very seriously. Our commitment to Taiwan is rock solid and contributes to the maintenance of peace and stability across the Taiwan Strait and within the region"
Tense cross-strait tensions and the surge of Chinese military jets into Taiwan's air defence zone, set off alarms that Beijing could try bolder moves to bring in what it views as a "rogue province" under its control.
Chinese President Xi Jinping pledged "peaceful reunification" in a key speech on October 8, but did not rule out military options.
Washington has long followed a policy of "strategic ambiguity" on the question of military intervention in the event of a Chinese attack.
But there've been clearer signs of US-Taiwan relations warming.
Oudkirk's remarks came after Taiwanese leader Tsai Ing-wen told CNN that a small team of U.S. soldiers are on the democratically-ruled island, to provide support and training to local troops.
While the United States, like most countries, has no formal ties with the Chinese-claimed island it is its most important international backer and main arms supplier.
President Joe Biden's administration has moved to restate that support, to the anger of Beijing.