Taiwan President Lai Ching-te departed Saturday for a stopover on US soil as part of a week-long tour of the Pacific, which has ignited fiery threats from Beijing.

China considers self-governed Taiwan to be part of its territory and opposes any international recognition of the island and its claim to be a sovereign state. 

Lai, on his first trip abroad since taking office in May, will stop over in Hawaii and the US territory of Guam as he visits Taiwan's allies Marshall Islands, Tuvalu and Palau.

They are the only Pacific island nations among the 12 remaining allies that recognise Taiwan, after China poached others with promises of aid and investment.

In a speech shortly before take-off, Lai said the tour "ushered in a new era of values-based democracy" and he thanked the US government for "helping to make this trip a smooth one".

Lai said he wanted to "continue to expand cooperation and deepen partnerships with our allies based on the values of democracy, peace and prosperity."

The trip has elicited a furious response from China, which has vowed to "resolutely crush" any attempts for Taiwan independence.

China and Taiwan have been ruled separately since 1949 when Chiang Kai-shek's nationalist forces were defeated by Mao Zedong's communist fighters and fled to the island. 

'Taiwan matters'

Taiwan lives under the constant threat of an invasion by China, which has refused to rule out using force to bring the island under its control. 

Beijing deploys fighter jets, drones and warships around Taiwan on a near-daily basis to press its claims, with the number of sorties increasing in recent years.

Taiwanese government officials have previously stopped over on US soil during visits to the Pacific or Latin America, angering China, which has sometimes responded with military drills around the island.

Lai's tour of the Pacific was an opportunity for him "to show those countries and the world that Taiwan matters", said Bonnie Glaser, a Taiwan-China affairs expert at the German Marshall Fund of the United States.

"I think that the People's Republic of China always wants to leave the impression that Taiwan is isolated and it is dependent on the PRC," Glaser told AFP, using China's official name.

"When Taiwan's president travels outside Taiwan, it's a reminder that there are countries in the world that value their diplomatic relationships with Taiwan," she said.

"And of course, when he transits the United States, it's a reminder, I think, to the public of Taiwan, that the United States and Taiwan have a close partnership."

The US is Taiwan's most important backer and biggest supplier of arms, but Washington does not have official diplomatic relations with Taipei.

Lai's trip follows the US approving the proposed sale to Taiwan of spare parts for F-16 fighter jets and radar systems, as well as communications equipment, in deals valued at $385 million in total.

Earlier this month, Taiwan's foreign minister Lin Chia-lung met with European Parliament members in Brussels.

It was part of a trend of more senior Taiwanese officials travelling abroad and countries publicly receiving them despite the risk of suffering retaliation from China, Glaser told AFP.

"I think there's safety in numbers — the more countries that do something, the more that other countries are willing to do it," Glaser said.

"There's also greater awareness of how aggressive and assertive China has been, and so countries are willing, to some extent, to stand up to China because they don't like China's behavior," she said. 

"And there is recognition of Taiwan's role in the world, especially in semiconductor chips."

by Allison Jackson with Akio Wang on board the plane