Ms Tsai arrived in New York on Wednesday on her way to Central America, and on her way back to Taipei next week will stop in Los Angeles where she is expected to meet U.S. House Speaker Kevin McCarthy.
The U.S. and Taiwan are closer than ever, Taiwan's President Tsai Ing-wen told supporters during a stopover in New York that so far, according to Taipei and Washington, has not triggered unusual military actions by China.
Ms Tsai arrived in New York on Wednesday on her way to Central America, and on her way back to Taipei next week will stop in Los Angeles where she is expected to meet U.S. House Speaker Kevin McCarthy, an interaction China has warned could lead to a "serious confrontation" in U.S.-China relations.
The visit comes at a time when U.S. relations with China are at what some analysts see as their worst level since Washington normalized ties with Beijing in 1979 and switched diplomatic recognition from Taipei.
Beijing says Taiwan belongs to "one China" and, as a Chinese province, has no right to state-to-state ties. Taiwan disputes this.
On what is her first U.S. stopover since 2019, Ms Tsai touted Taiwan's economic, security and diplomatic achievements in a closed-door speech on Wednesday night to overseas Taiwanese in New York, her office said in a statement on Thursday, calling the island a "beacon of democracy in Asia."
"In particular, the relationship between Taiwan and the United States is closer than ever," she said, noting "significant progress" in economic and security cooperation.
Ms Tsai said Taiwan Semiconductor Manufacturing Co Ltd (TSMC) (2330.TW), the world's largest contract chipmaker, establishing a factory in Phoenix, Arizona, demonstrated the island's technological strength.
Though Taiwan faced "enormous challenges," it would not be isolated, Ms Tsai said. She also thanked the U.S. government for implementing security agreements with Taiwan, including nine announced arms sales by President Joe Biden
Laura Rosenberger, chair at the Washington headquarters of the American Institute in Taiwan (AIT), a U.S. government-run, non-profit organization that carries out unofficial relations with Taiwan, and New Jersey Governor Phil Murphy also attended the event, according to Tsai's office.
Ms Tsai was due to speak at a Hudson Institute think tank event on Thursday, according to sources, but Taiwan's de facto embassy in the U.S. has said all of her engagements in New York are closed to the press and public.
No Chinese military action
Taiwan's defence ministry, in its daily update on China's military activities, said that from Wednesday to Thursday morning it had not spotted any Chinese aircraft entering Taiwan's air defence zone or crossing the median line of the Taiwan Strait, which serves as an unofficial barrier.
China's air force flies almost daily into the air defence zone, or across the median line, in which Taiwan calls "grey zone" warfare designed to test and wear out its forces.
A senior Taiwan security official said earlier that the island expects a less severe reaction from Beijing to a Tsai-McCarthy meeting than when then-House Speaker Nancy Pelosi visited Taipei last year, something that prompted China to stage major military drills.
"She will be meeting in the United States, so the political complexity is not as high as the speaker coming to Taiwan," Taiwan National Security Bureau Director-General Tsai Ming-yen told Taiwan's parliament.
He added that Taiwan had been conducting dry runs on responses to a rise in tensions while the president is away, including when she is flying, and that she can be reached at any time to meet her top security officials.
The White House, which urged China on Wednesday not to use Tsai's "normal" stopover in the U.S. as a pretext to increase aggressive activity against Taiwan, also said it had seen "no tangible reaction" yet from China.
"I think we've all seen them react in a rhetorical way, but we've seen no indication that there's been any other type of reaction," White House national security spokesperson John Kirby told reporters.
A meeting with Kevin McCarthy would be the first between a Taiwanese leader and a U.S. House Speaker on U.S. soil, although it is seen as a potentially less provocative alternative to Mr McCarthy visiting Taiwan, something he has said he hopes to do.
As House speaker, Kevin McCarthy is third in the U.S. leadership succession hierarchy, and China has repeatedly warned U.S. officials not to meet Ms Tsai, seeing it as showing support for the island's desire to be recognized as a separate country.
China's Taiwan Affairs Office spokesperson Zhu Fenglian said in Beijing on Wednesday that if President Tsai met with McCarthy, China would "definitely take measures to resolutely fight back" and Xu Xueyuan, charge d'affaires at China's Washington embassy, said such a meeting "could lead to another serious confrontation in the China-U.S. relationship."
Washington, like most countries, maintains only unofficial ties with Taipei, but U.S. law requires the government to provide the island with the means to defend itself and it facilitates unofficial stopover visits.
The U.S. transit is Tsai's seventh since taking office in 2016 and comes amid concerns in the U.S. and elsewhere that Russia's invasion of Ukraine might embolden China to move against Taiwan.