BEIJING >> China threatened retaliation today if U.S. House Speaker Kevin McCarthy meets with Taiwan’s president during her upcoming trip through Los Angeles.

President Tsai Ing-wen left Taiwan today on a tour of the island’s diplomatic allies in the Americas which she framed as a chance to demonstrate Taiwan’s commitment to democratic values on the world stage.

Tsai is scheduled to transit through New York on Thursday before heading to Guatemala and Belize. She is expected to stop in Los Angeles on her way back to Taiwan on April 5, when a meeting with McCarthy is tentatively scheduled.

The planned meeting has triggered fears of a heavy-handed Chinese reaction amid heightened friction between Beijing and Washington over U.S. support for Taiwan and trade and human rights issues.

The spokesperson for China’s Taiwan Affairs Office, Zhu Fenglian, denounced Tsai’s stopovers and demanded that no U.S. officials meet with her.

“We firmly oppose this and will take resolute countermeasures,” Zhu said at a news conference. The U.S. should “refrain from arranging Tsai Ing-wen’s transit visits and even contact with American officials and take concrete actions to fulfill its solemn commitment not to support Taiwan independence,” she said.

Beijing claims self-governing Taiwan is part of its territory and threatens to bring the island under its control by force if necessary.

Speaking later today, Chinese Foreign Ministry spokesperson Mao Ning said China will “closely follow the development of the situation and resolutely defend national sovereignty and territorial integrity.”

Mao said the United States was “conducting dangerous activities that undermine the political foundation of bilateral ties.”

McCarthy, a Republican from California, has said he will meet with Tsai when she is in the U.S. and has not ruled out the possibility of traveling to Taiwan in a show of support.

Following a visit by then-House Speaker Nancy Pelosi to Taiwan in 2022, Beijing launched missiles over the area, deployed warships across the median line of the Taiwan Strait and carried out military exercises in a simulated blockade of the island. Beijing also suspended climate talks with the U.S. and restricted military-to-military communication with the Pentagon.

Tsai told reporters before boarding her plane that “I want to tell the whole world democratic Taiwan will resolutely safeguard the values of freedom and democracy and will continue to be a force for good in the world, continuing a cycle of goodness, strengthening the resilience of democracy in the world.”

“External pressure will not obstruct our resolution to engage with the world,” she said.

Beijing has recently ramped up diplomatic pressure against Taiwan by poaching its dwindling number of diplomatic allies while also sending military fighter jets flying toward the island on a near-daily basis. Earlier this month, Honduras established diplomatic relations with China, leaving Taiwan with only 13 countries that recognize it as a sovereign state.

U.S. administration officials in a call with reporters ahead of Tsai’s arrival underscored that her transit is in line with what she and her predecessors have done in the past. Tsai has made six transits through the U.S. — stopovers that have included meetings with members of Congress and members of the Taiwanese diaspora — during her presidency.

The officials, who spoke on the condition of anonymity to discuss the sensitive visit, said Tsai is also expected to meet with American Institute in Taiwan chair Laura Rosenberger. AIT is the U.S. government-run nonprofit that carries out unofficial relations with Taiwan.

One official added that “there is absolutely no reason” for Beijing to use Tsai’s stopover “as an excuse or a pretext to carry out aggressive or coercive activities aimed at Taiwan.”

Beijing sees official American contact with Taiwan as encouragement to make the island’s decades-old de facto independence permanent, a step U.S. leaders say they don’t support. Pelosi was the highest-ranking elected American official to visit the island since then-Speaker Newt Gingrich in 1997. Under its “one China” policy, the U.S. acknowledges Beijing’s view that it has sovereignty over Taiwan, but considers Taiwan’s status as unsettled. Taiwan is an important partner for Washington in the Indo-Pacific.

U.S. officials are increasingly worried about China attempting to make good on its long-stated goal of bringing Taiwan under its control. The sides split at the end of a civil war in 1949 and Beijing sees U.S. politicians’ visits as conspiring with Tsai’s pro-independence Democratic Progressive Party to make the separation permanent and stymy China’s rise as a global power.

The 1979 Taiwan Relations Act, which has governed U.S. relations with the island, does not require Washington to step in militarily if China invades but makes it American policy to ensure Taiwan has the resources to defend itself and to prevent any unilateral change of status by Beijing.

Tensions spiked earlier this year when U.S. President Joe Biden ordered a Chinese spy balloon shot down after it traversed the continental United States. The Biden administration has also said U.S. intelligence findings show that China is weighing sending arms to Russia for its war in Ukraine, but has no evidence Beijing has done so yet.

China, however, has provided Russia with an economic lifeline and political support, and President Vladimir Putin and Chinese leader Xi Jinping met in Moscow earlier this month. That was the first face-to-face meeting between the allies since before Russia launched its invasion of Ukraine more than a year ago.

The Biden administration postponed a planned visit to Beijing by Secretary of State Antony Blinken following the balloon controversy but has signaled it would like to get such a visit back on track.

Foreign Ministry spokesperson Mao said the blame for tensions lies squarely with Washington for boosting relations with Tsai. Beijing has frozen almost all contacts with Tsai’s administration since shortly after she was elected to the first of her two terms in 2016.

“It is not that China overreacts. It is that the U.S. kept emboldening Taiwan independence forces, which is egregious in nature,” Mao said at a daily briefing.

Tsai’s state visits coincide with a 12-day trip to China by her predecessor, Ma Ying-jeou, of the pro-unification Nationalist Party, in an appeal to voters whose descendants arrived with Chiang Kai-shek’s defeated forces in 1949.

Ma has been visiting sites in the former Nationalist capital of Nanjing and emphasizing historical and cultural links between the sides, while avoiding the politically sensitive topics of China’s determination to eliminate Taiwan’s international presence and refusal to recognize its government.

Tsai is barred from seeking a third term and her party is widely expected to nominate Vice President Lai Ching-te to run for the presidency in January.

Associated Press writers Huizhong Wu in Taipei, Taiwan, and Aamer Madhani in Washington, D.C., contributed to this report.