An unofficial delegation dispatched by the U.S. government signaled readiness to further deepen ties with Taiwan in talks with Taiwan President Tsai Ing-wen on Thursday, amid heightened tensions between the United States and China over the self-ruled island.

Former Sen. Chris Dodd said in remarks that the bipartisan delegation was sent at the request of President Joe Biden and meant to reaffirm the U.S. commitment to "deepening our cooperation on the multitude of interests that we share in common."

Taiwanese President Tsai Ing-wen. (Kyodo)

"And we look forward to working with Taiwan to advance our shared values, prosperity and security," he added in the talks at Tsai's office in Taipei, part of which were streamed online.

Tsai expressed her thanks to the Biden administration, saying it has repeatedly expressed support for Taiwan. She also called for stronger cooperation with the United States in economic and energy-related areas.

The delegation that also included two former deputy secretaries of state, Richard Armitage and James Steinberg, drew a strong reaction from mainland China, which views it as official in nature.

Chinese Foreign Ministry spokesman Zhao Lijian lambasted interactions between the United States and the democratic, self-governed island, saying, "The Taiwan issue concerns China's sovereignty and territorial integrity as well as its core interests."

"China's determination to safeguard national sovereignty and security interests is unwavering," Zhao told reporters in Beijing, urging the United States to stop sending wrong signals to "Taiwan independence" separatist forces.

The U.S. delegation, which arrived in Taiwan on Wednesday, is also scheduled to hold talks with Premier Su Tseng-chang during its visit.

The visit is tied to the 42nd anniversary of the enactment of the 1979 Taiwan Relations Act, under which the United States supplies the island with arms and spare parts to enable it to maintain sufficient self-defense capabilities, according to a senior U.S. government official.

China has recently been increasing pressure on the island, which it regards as a renegade province awaiting reunification by force if necessary. Its repeated incursions into Taiwan's air defense identification zone and naval exercises in nearby waters have heightened concerns in the United States about a possible Chinese invasion.

On Wednesday, Chinese maritime authorities announced a live-fire drill from Thursday to Tuesday in the South China Sea near Taiwan, ordering ships to stay away from waters south of the Taiwan Strait off mainland China's Guangdong Province.

Taiwan and mainland China have been separately governed since they split as a result of a civil war in 1949. The United States switched its diplomatic recognition from Taipei to Beijing in 1979.

China has endeavored to undermine Taiwan's quest for international recognition, but the administration of former U.S. President Donald Trump forged close ties with Taipei, making relations between Beijing and Washington more fragile.

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