The United States stands firm behind its commitments to Taiwan and allies in the region, a delegation of former senior U.S. defence and security officials sent by President Joe Biden said on Wednesday.

Collaboration between the United States and Taiwan is stronger and more expansive than ever before, former chairman of the U.S. Joint Chiefs of Staff Mike Mullen said during his visit to the democratic island.

Mullen is in Taiwan leading a delegation of former top officials sent by U.S. President Joe Biden. The trip is happening against the backdrop of Russia's invasion of Ukraine, which is being closely followed in Taiwan.

"The United States will continue to oppose any unilateral changes to the status quo and will continue to support a peaceful resolution of cross-strait issues, consistent with the wishes and best interests of the people of Taiwan," Mullen told Taiwan President Tsai Ing-wen in a meeting broadcast live on Facebook.

"I do hope by being here with you, we can reassure you and your people, as well as our allies and partners in the region, that the United States stands firm behind its commitments."

Taiwan, claimed by China as its own territory, is on alert in case Beijing tries to use the opportunity to make a move on the island, though the government has reported no unusual Chinese manoeuvres.

Beijing has vowed to bring it under Chinese control, by force if necessary, and has increased its military and political pressure against Taiwan to try and force the island to accept China's sovereignty. Taiwan has vowed to defend itself if attacked.

The delegation will also meet Taiwan Defence Minister Chiu Kuo-cheng.

Mullen's delegation marks the first public visit of a group of former officials to Taiwan at Biden's behest since April 2021, when former U.S. Senator Chris Dodd and former Deputy Secretaries of State Richard Armitage and James Steinberg travelled there and met with Tsai.