Taiwanese President Tsai Ing-wen has met with the Speaker of the US House of Representatives, Kevin McCarthy. She says her democracy is facing "unprecedented challenges."
Tsai was returning from a visit to Central America and made a stopover on Wednesday at the Ronald Reagan Library in California.
She met with McCarthy and other Republican and Democratic lawmakers in talks orchestrated to show solidarity.
Tsai said, "To preserve peace, we must be strong. I would like to add that we are stronger when we are together."
McCarthy is the most senior lawmaker to meet with a Taiwanese leader on US soil.
He said, "The friendship between the people of Taiwan and America -- as a matter of profound importance to the free world, it is critical to maintain economic freedom, peace and regional stability."
McCarthy later said the US needs to continue arms sales to Taiwan and ensure those deliveries arrive on-time.
Tsai met with McCarthy's predecessor, Nancy Pelosi, in Taipei in August. Chinese leaders responded to that visit by staging their largest-ever military exercise around Taiwan.
US Secretary of State Antony Blinken has downplayed Tsai's stopover in the US, describing it as a "transit." He added that Chinese officials should not use it as an excuse to "ratchet up tensions."