China threatened on Wednesday that it would respond with “strong retaliation” if the planned meeting between Taiwan President Tsai Ing Wen and US House Speaker Kevin McCarthy, which Beijing describes as a meeting, takes place. “serious provocation”. The meeting should take place during the visit that the president of the autonomous island has scheduled to visit Los Angeles after a ten-day trip through Central America.

Chinese State Council Taiwan Affairs Office (Executive) spokeswoman Zhu Fenglian said the Taiwanese authorities’ “stopover” in the US is essentially a provocative act for “relying on the US to independence.” China, which claims Taiwan as its own, democratically governed territory, has repeatedly warned US officials not to meet with Tsai, seeing it as supporting the island’s desire to be considered a separate country.

The meeting between Tsai and McCarthy “seriously violates the one-China principle, damages China’s sovereignty and territorial integrity, and destroys peace and stability in the Taiwan Strait,” Zhu said. “We are strongly opposed to it and will definitely take steps to counterattack with determination,” he added without elaborating.

President Tsai is crafting a diplomatic agenda to strengthen ties with the West and assert her island’s autonomy while trying to avoid moves that could spark a crisis with China, though she remains defiant. “External pressure will not prevent Taiwan from relating to the world,” the president responded Wednesday to Beijing’s threats as she left for the United States.

“We are calm and confident, we will not give in or provoke. Taiwan will firmly walk the path of freedom and democracy and go further into the world. Even if this path is hard, Taiwan is not alone,” Tsai added.

China staged military drills around Taiwan last August when then-US House Speaker Nancy Pelosi visited Taipei, and the Taiwanese military has said they are watching for any Chinese moves while Tsai is find abroad.

Diplomatic pressure against Taiwan has increased recently, with Beijing recruiting a dwindling number of Taipei’s diplomatic allies while sending fighter jets toward the island almost daily. Earlier this month, Honduras established diplomatic relations with China, leaving Taiwan with only 13 countries that recognize it as a sovereign state.

Tsai will travel to Guatemala and Belize, first via New York and then Los Angeles on the way back. Although not officially confirmed, he is expected to meet McCarthy while in California on April 5.

Tsai’s transits will come at a time when US relations with China are at what some analysts consider their worst since Washington normalized ties with Beijing in 1979 and changed Taipei’s diplomatic recognition.

Taiwan is China’s most sensitive territorial issue and a major bone of contention with Washington, which, like most countries, maintains only unofficial ties with Taipei. However, the United States Government is required by law to provide the island with the means to defend itself.