China mobilized warships in the waters around Taiwan on Thursday after the meeting between the island’s president, Tsai Ing-wen, and the speaker of the US House of Representatives.

Ignore Beijing’s warningsmet Taiwanese leader Kevin McCarthy in Los Angeles on Wednesday during a stopover on his return from Guatemala and Belize, two of the self-governing island’s last allies.

Chinawhich considers Taiwan a rogue province, reacted immediately, pledging “firm and effective measures to protect national sovereignty and territorial integrity”.

“The United States and Taiwan conspired” to “strengthen their relations”which “seriously undermines Chinese sovereignty” and “sends a bad signal of support to the Taiwanese separatists,” Chinese Foreign Ministry spokeswoman Mao Ning complained.

Hours before the meeting, China had already deployed an aircraft carrier near the island.

Taiwan’s Defense Ministry also announced the detection at 06:00 local time (Wednesday 22:00 GMT) of three warships and an anti-submarine helicopter crossing the island’s air defense identification zone.

“The armed forces have been monitoring the situation and deploying combat air patrol aircraftnaval vessels and land-based missile systems are responding to these activities,” he added.

China and Taiwan have been de facto separated since 1949, when communist forces prevailed in the civil war against the nationalists, who sought refuge on the island.

Beijing sees national “reunification” as a priority issue and says it will not hesitate to use force if necessary to achieve it.

Tsai: “We are not isolated”

In application of the principle of “one China”, recognized a priori by the United States, Beijing opposes any formal relationship between the island’s leaders and those of other countries.

In August, after a visit to Taipei by McCarthy’s predecessor, Democrat Nancy Pelosi, China deployed warships, fighter jets and fired missiles around the island.

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To avoid a similar episode, McCarthy stopped traveling to Taiwan and opted for this meeting in California, which has caused a less intense response from China at this point.

Before leaving the United States, Tsai said the island’s Department of Homeland Security was closely monitoring the situation.

“Our action is to ensure safe navigation on the high seas for our ships and prevent Chinese interference in our territorial waters,” he said, after Chinese authorities threatened to carry out inspections on cargo and passenger ships.

On the other hand, the island’s president thanked Washington’s “unwavering support” and said it was proof that the Taiwanese were not “isolated” or “alone.”

“Diplomacy”

McCarthy, second in line for the presidential succession, said so the U.S.-Taiwan friendship was “vital to the preservation of economic freedom, peace, and regional stability.” The United States recognized Beijing in 1979, but it remains a major ally of Taiwan and its largest arms supplier.

The US Legislative Leader advocated keeping this support for the island because “we know historically that it is best to provide arms to enable people to avoid war”. State Department spokesman Vedant Patel urged China to “cease its military, diplomatic and economic pressure on Taiwan” and instead opt for “constructive diplomacy”.

This new chapter of tension coincides with the arrival in Taiwan of an eight-member delegation from the US Congress to discuss trade and security. Support for the island is one of the few consensus between Republicans and Democrats in the US Congress.

Tsai, who has been in power since 2016, will end her term in 2024 and her party will face opposition from rivals deemed closer to Beijing.

The leader has positioned himself as a defender of the status quo, a de facto though not openly recognized independence, as China presses to isolate and wrest its last diplomatic allies from the island.

After Beijing’s recent recognition by Hoduras, only thirteen countries officially recognize Taiwan.