Another US congressional delegation is visiting Taiwan as tensions with China remain high over its claims to the self-governed island.
A steady stream of US visitors has come to meet Taiwanese officials since US House Speaker Nancy Pelosi visited in early August.
China in response has stepped up its military harassment, sending warships, warplanes and even drones towards the island on a daily basis.
Led by Florida Democrat Stephanie Murphy, the delegation arrived on Wednesday and met on Thursday with Taiwanese President Tsai Ing-wen, whose administration China has relentlessly sought to deprive of diplomatic recognition.
Referring to China's military threats, Tsai said the delegation's visit "conveys rock solid support for Taiwan from the US Congress".
"Taiwan will not bow to pressure or coercion," Tsai said. "We will defend our democratic institutions and way of life. Taiwan will not back down."
Murphy replied that Congress "should advocate for greater Taiwanese participation in international organisations".
"Taiwan has shown itself to be a responsible member of the international community, especially in public health issues, and it deserves to participate in international fora when appropriate," she said.
Murphy is among lawmakers who introduced a bill that would allow the US to lend weapons to support Taiwan, similar to a bill that had passed to lend weapons to Ukraine.
Last week, the Biden administration approved a $US1 billion ($A1.5 billion) arms sale to Taiwan.
Murphy also said deepening economic relations with Taiwan was "one of the most important things Congress can do right now", particularly by pushing for a "high-quality free trade agreement" between the sides.
Negotiations are under way on a trade pact.
The other American lawmakers visiting are Democrat Kaiali'i Kahele and Republicans Scott Franklin, Joe Wilson, Andy Barr, Darrell Issa, Claudia Tenney and Kat Cammack.