A delegation of US congressmen arrived in Taiwan on Sunday for an unannounced visit, a US diplomatic source on the island said, according to AFP.

According to the American Institute in Taiwan, the de facto US embassy on the island, the five-person visit — one senator and four representatives, Democrats and Republicans — scheduled to last until Monday comes days after Beijing wrapped up its biggest a story within a story. The largest military maneuvers around Taiwan in response to the visit of the Speaker of the US House of Representatives, Nancy Pelosi.

Taipei accused China of using Pelosi’s visit as a pretext to prepare for an invasion.

In response, the US reaffirmed its commitment to the region.

Washington will strengthen trade ties with Taiwan and build new air and sea bridges across the strait in response to China’s “provocative” actions, White House Asia-Pacific coordinator Kurt Campbell said on Friday.

China considers Taiwan, with a population of about 23 million, as one of its provinces, which it has not yet been able to reunite with the rest of its territory since the end of the Chinese Civil War (1949).

Beijing opposes any initiative that gives the Taiwanese government international legitimacy, and opposes any official contacts between Taiwan and other countries.

US officials often visit the island, but China views the visit by Ms Pelosi, one of the most senior US officials, as a serious problem.

“The delegation will meet with high-ranking Taiwanese officials to discuss US-Taiwanese relations, regional security issues, trade and investment, and climate change,” the American institute said.

Taiwan’s foreign minister welcomed the visit.