New York: Taiwan's vice president and presidential candidate William Lai's stopover in the US on Sunday en route to Paraguay irked China, denouncing the move, its foreign ministry branded him a "troublemaker through and through," according to CNN.

On his way to Paraguay, where he will witness Santiago Pena's inauguration as president on August 15, Lai arrived in New York on Saturday. Taiwan's sole ally in South America is Paraguay.

In a statement shared on X, previously known as Twitter, Lai said he was “Happy To Arrive” in New York – an “icon of liberty, democracy and opportunities.”

Ahead of Lai’s arrival, US government officials said they expected his transit to occur “without incident.”

“These transits of senior officials are unofficial, in keeping with our US One China policy,” a senior administration official told CNN on July 16, calling such transits “fairly common.”

Lai last transited the US in January 2022.

China’s ruling Communist Party claims Taiwan as part of its territory, despite never having controlled it, and has not renounced the use of force to take the self-ruled island, CNN reported.

Shortly after Lai’s arrival, China’s foreign ministry said it “firmly opposes” any official interaction between the US and Taiwan and any “‘Taiwan independence’ separatists to the US.”

“China deplores and strongly condemns the US decision to arrange the so-called ‘stopover,’” it said in a statement.

“Lai clings stubbornly to the separatist position for ‘Taiwan independence’. He is a troublemaker through and through,” it continued.

The ministry also said Taiwan was the “core of the core interests of China” and urged the US to abide by the one-China principle – adding it was “closely following” developments and “would take resolute and strong measures to safeguard its sovereignty and territorial integrity.”

Trips to the US by Taiwan’s officials are referred to as “transits” instead of visits because the US does not have formal diplomatic relations with the government of Taiwan and the stopovers come as part of an unofficial trip en route to another destination, according to CNN.

Lai is due to transit through San Francisco on August 16 on his return to Taipei, Taiwan’s vice foreign minister Alexander Yui said during a media briefing earlier this month.