Washington “is doing its utmost to smear and slander China’s diplomatic efforts, and putting in a word for Taiwan to expand its space on the international stage”, foreign ministry spokesman Mao Ning told a regular press conference.

Nauru, a tiny island nation in the South Pacific, said yesterday it was switching diplomatic ties from Taiwan to China.

The announcement came just days after independence-leaning candidate Lai Ching-te – loathed by Beijing – won the Taiwanese presidential election.

China views Taiwan as part of its own territory and has vowed to one day seize it, by force if necessary.

Beijing does not maintain relations with countries that recognise Taiwan and has stepped up efforts to diplomatically isolate Taipei in recent years.

“The US is blatantly making irresponsible remarks about a decision made independently by a sovereign state,” Mao said.

“This seriously violates the one China principle … seriously interferes in China’s internal affairs, and seriously violates basic norms of international relations,” she added.

“China is strongly dissatisfied and firmly opposes this.”