Isolated Taiwan president puts bumpy tour behind him

China, which has vowed to bring Taiwan back under mainland rule, by force if necessary, has blocked Taiwan's repeated U.N. applications, saying only sovereign nations should be able to join the global organisation.

Seeking a U.N. seat and more independence from China have been key parts of Chen's platform since he was first elected in 2000.

"During the trip, some things came up, so Chen was furious," said Shane Lee, a political science professor with Chang Jung University in Taiwan. "He's very bitter about being betrayed by those countries."

In one such country, Nicaragua, Chen also would not promise on the spot to fund a request for power generation and medical supplies worth $38 million (18.9 million pounds), the president's office said. That sort of request must go through the Taiwan's legislature, a presidential spokesman said.

But local media said he pledged $35 million to Honduras.

To cap it all, as Chen met the Central American foreign leaders, a Chinese foreign ministry official urged Taiwan's six Central American diplomatic allies to follow Costa Rica's lead and defect to China.

And Costa Rican President Oscar Arias defended his country's decision to switch allegiance. "Not to recognise a country with a fifth of the world's population is ridiculous," he said.

Lo Chih-cheng, of Soochow University in Taiwan, said Chen had showed some frustration with his trip.

"That's inevitable given what he's trying to do," Lo said.

"But he's a very determined person."