TAIPEI, Taiwan: A delegation of former senior U.S. defense and security officials have arrived in Taipei.

However, the visit was denounced by China, especially as it is occurring during Russia’s invasion of Ukraine.

The visit, led by former chairman of the Joint Chiefs of Staff retired Navy admiral Mike Mullen, comes at a time when Taiwan increased its alert level, concerned about China taking advantage of a distracted West.

Beijing claims the democratically governed island as its own, and has vowed to bring it under Chinese control, by force, if necessary.

Mullen, who served under former presidents George W. Bush and Barack Obama, was accompanied by Meghan O’Sullivan, former deputy national security adviser under Bush, and Michele Flournoy, former undersecretary of defense under Obama.

A U.S. official told Reuters that the trip is intended to “demonstrate our continued robust support for Taiwan.”

The group, which touched down in a private jet at Taipei’s downtown Songshan airport and was met by Taiwan Foreign Minister Joseph Wu, will meet President Tsai Ing-wen this week.

China describes Taiwan as the most sensitive and important issue in its ties with the U.S., and any high-level interactions typically upset Beijing.

“The will of the Chinese people to defend our country’s sovereignty and territorial integrity is immovable. Whoever the U.S. sends to show support for Taiwan is bound to fail,” said Chinese Foreign Ministry spokesperson Wang Wenbin, in response to the visit.

Meanwhile, Taiwan Premier Su Tseng-chang has told reporters that the trip showed “the importance, both of the Taiwan-US relationship and Taiwan’s position,” as well as the continuing U.S. support for the island.

As part of what the U.S. military calls routine activities, a U.S. warship sailed through the sensitive Taiwan Strait this week. China described the ship’s presence as “provocative.”

Wang used even stronger terms, stating, “If the U.S. is trying to threaten and pressure China with this, then we need to tell them that in the face of the Great Wall of steel forged by 1.4 billion Chinese people, any military deterrence is but scrap metal.”