Taiwan has ordered diplomats to shore up relations with its remaining allies after Costa Rica became the latest country to switch allegiance to China.
China paid Costa Rica a huge sum, says Taiwan's James Huang
Chinese and Taiwanese academics said that Costa Rica's move could trigger a domino effect, with other Latin American countries following suit.
Only 24 states now recognise Taiwan, which Beijing regards as a breakaway province.
Taiwan's foreign minister offered to resign over the setback.
"I've asked our embassies to take extreme precautions against any further pressure by the Chinese communists," said Foreign Minister James Huang, whose resignation offer was refused by the president.
Opposition legislator John Chiang warned that other Latin American countries might now also switch allegiance to mainland China.
"We must be on our guard as the Costa Rican move might trigger a domino effect. We should not underestimate the grave diplomatic situation Taiwan is in," he said.
Vice President Annette Lu announced she would travel to Paraguay in July to celebrate 50 years of diplomatic relations with the country.
"Now we have to step up our diplomatic work," she said.
Costa Rican President Oscar Arias said his country needed to develop closer ties with China for economic reasons.
China offered Costa Rica "an astronomical figure" to leave Taipei's diplomatic fold, according to Mr Huang.
Costa Rica's president said the split was made for economic reasons
Taiwan and China have been governed separately since the end of a civil war in 1949, and both often accuse each other of using "chequebook diplomacy" to attract allies.
China sees Taiwan as part of its territory has threatened to use force if the island ever moved to declare formal independence.
It refuses to have diplomatic ties with nations that recognise Taiwan.
Chinese Foreign Ministry spokeswoman Jiang Yu called on other countries in the region to establish diplomatic relations with China.
"We are ready to establish normal state relations with these countries. The Taiwan question is the sole obstacle to establishing diplomatic ties," she told a briefing.
The remaining 24 nations that are allied to Taipei are mostly small and impoverished nations in the Caribbean, Africa and the south Pacific, including the Solomon Islands, Nicaragua, Panama and Burkina Faso.