CNN  — 

Taiwan’s relationship with the United States has “never been closer,” its President Tsai Ing-wen said after arriving in New York City Wednesday, as Beijing warned her visit could lead to “serious confrontation” between China and the US.

Taiwan faced “tremendous challenges,” Tsai said from the city, where she is making the first of two planned stopovers in the United States on either side of an official visit to Central America.

“We know that we are stronger when we stand together in solidarity with fellow democracies. Taiwan cannot be isolated and we do not take friendship for granted,” Tsai said at a banquet with members of the Taiwanese-American community, according to footage from CNN’s Taiwan affiliate SET TV.

Tsai’s visit comes at a time of heightened tensions between the US and China and has already sparked sharp condemnation from Beijing – which claims democratic Taiwan as its territory, despite never having controlled it.

Tsai’s US transit could lead to a “serious” confrontation in the US-China relationship and have a “severe impact” on their ties, China’s charge d’affaires Xu Xueyuan told reporters in Washington on Wednesday.

“What the US has done seriously undermines China’s sovereignty and territorial integrity,” Xu said, adding that the US should bear “all consequences.”

Tsai’s travels have been under particular scrutiny following reports that she will meet US House Speaker Kevin McCarthy during one of her unofficial stopovers in the US – a potential event Beijing has vowed to “resolutely fight back” against should it go ahead.

Taiwan has not confirmed such a meeting nor provided details of Tsai’s itinerary while in the US.

Beijing launched extensive, days-long military exercises around the island last August, following a visit from then-US House Speaker Nancy Pelosi to Taipei.

Pelosi was the highest ranked American official to visit Taiwan in 25 years, and the trip sparked accusations from Beijing that the US was changing the nature of its relationship with Taiwan – a claim US officials have repeatedly refuted.

Tsai said via Facebook Wednesday that her delegation was welcomed by Laura Rosenberger, chair of the American Institute in Taiwan (AIT), the organization that carries out unofficial US relations with Taiwan. Rosenberger and New Jersey Governor Phil Murphy gave remarks at the banquet welcoming Tsai Wednesday evening.

Speaking at the event, Tsai thanked the US government for “fulfilling its security commitments to Taiwan,” and referenced Congressional support for Taiwan’s self-defense capabilities as well as the Biden administration arms sales to Taiwan.

The US is bound by law to sell arms to Taiwan for its self-defense, though it ended its formal diplomatic relationship with Taipei in 1979 when it recognized the government in Beijing.

Because of the unofficial relationship the US has with Taiwan, Tsai’s transit is not characterized as an official visit in order to keep the US within the longstanding “One China” policy.

Under the “One China” policy, the US acknowledges China’s position that Taiwan is part of China, but has never officially recognized Beijing’s claim to the island of 23 million.

US officials have sought to downplay her stopovers as nothing unusual and urged Beijing not to use them as an excuse to carry out “aggressive or coercive activities” aimed at Taiwan.

Tsai had previously transited the US six times while president, according to US officials.

On Wednesday National Security Council spokesman John Kirby stressed that such transits were “private” and “unofficial.”

“The People’s Republic of China should not use this transit as a pretext to step up any aggressive activity around the Taiwan Strait. The United States and China have differences when it comes to Taiwan, but we have managed those differences for more than 40 years,” Kirby said.

In the weeks leading up Tsai’s visit, however, Beijing issued multiple condemnations and said they were reaching out to US counterparts regarding reports of a possible meeting with McCarthy, even as such a meeting on American soil could be seen as less provocative than a visit to Taiwan by a top US lawmaker.

Frictions between China and the US over the future of the democratic island have heightened in recent years.

Beijing has vowed to take the island, by force if necessary, and under leader Xi Jinping has ramped up military, diplomatic and economic pressure on the democracy, including enticing Taipei’s allies to switch their allegiance.

Tsai’s US transit is part of a broader international trip featuring state visits to two of Taiwan’s diplomatic allies, Guatemala and Belize, before transiting in Los Angeles for her April 7 return to Taiwan.

In remarks before her departure, Tsai said “external pressure” wouldn’t stop Taiwan from “moving toward international society.”

Guatemala and Belize are part of a handful of nations maintaining diplomatic relations with Taipei.

That number shrunk to 13 over the weekend, when Honduras formally established diplomatic ties with China and severed them with Taiwan.

Beijing does not have diplomatic relations with countries that recognize Taipei.

Honduran President Xiomara Castro will visit China “soon” to sign “auspicious agreements,” its foreign ministry said in a Tweet Wednesday, without specifying a date.