The tiny Pacific island of Nauru has severed formal diplomatic relations with Taiwan and switched its allegiance to China.

It announced the move as Beijing intensifies pressure on Taipei after its weekend election, which returned a pro-sovereignty candidate as president-elect.

The Nauru government said on Monday that “in the best interests” of the country and its people it was seeking full resumption of diplomatic ties with China, a move that will concern the United States and its allies, including Australia, over Beijing’s rising influence in the Indo-Pacific region.

Nauru is the first of Taiwan’s official diplomatic allies to abandon the island since Saturday’s poll, which resulted in Lai Ching-te, a nemesis of the Chinese Communist Party (CCP), being appointed as the next president in defiance of Beijing’s repeated calls not to elect him.

“This means that the Republic of Nauru will no longer recognise the Republic of China (Taiwan) as a separate country but rather as an inalienable part of China’s territory,” the country’s government said in a statement.

It added it would no longer have “any official relations or official exchanges” with the democracy of 23.5 million in a move that overshadowed a visit by an unofficial US delegation sent by Joe Biden, the US president, to congratulate Mr Lai on his election win.

Taiwan cut ties in return, announcing the termination of diplomatic relations with Nauru – a strategically located microstate of about 12,500 people in Micronesia – with “deep regret” and accusing Beijing of buying the island off.

“This timing is not only China’s retaliation against our democratic elections but also a direct challenge to the international order. Taiwan stands unbowed and will continue as a force for good,” it said.

“Once again, it proves that China’s trying everything they can – money diplomacy – to repress us,” Tien Chung-kwang, the deputy foreign minister, told a hastily arranged media briefing.

China’s foreign ministry said Beijing’s resumption of ties with Nauru “reflects the sentiments” of its people. Nauru has recognised China before, between 2002 and 2005.

Its decision to do so again leaves Taipei with only 12 formal allies, including Guatemala, Paraguay, Eswatini, Tuvalu and Palau, although Taiwan enjoys growing partnerships around the world, including with the UK and the US, its main arms supplier.

Allies dump Taiwan

Since Mr Lai’s Democratic Progressive Party (DPP) rose to power in 2016, China, which views the party as dangerous separatists, has picked off 10 of the countries the government previously had diplomatic relations with.

The Chinese Communist Party views the island as its own territory, even though it has never ruled there, and in recent years it has increased its efforts to isolate Taiwan by excluding it from international bodies and to protest even its informal relations with other countries.

Nauru, was a Japanese stronghold during the Second World War, when they occupied it and built an airfield.

Its move to pledge diplomatic allegiance to Beijing will set off alarm bells in Canberra and Washington about China’s Indo-Pacific ambitions.

Some 800 miles southwest of Nauru, a similar switch by the Solomon Islands from Taipei to Beijing in 2019 led to the signing of a secretive security pact with China and stoked western fears about the prospect of Chinese warships and troops being stationed about 1,200 miles from the Australian coast.