Thailand's military coup leaders faced international calls for a swift return to democracy on Wednesday, after vowing to choose a new prime minister within two weeks to replace ousted Thaksin Shinawatra.

Speaking less than 24 hours after leading a bloodless coup to oust the billionaire premier, army chief General Sonthi Boonyaratglin said it would take a year to produce a new constitution leading to a fresh general election.

The military leadership said it was looking at civilian candidates to replace Thaksin, who arrived in London on Wednesday from New York where he had been attending the U.N. General Assembly.

We have two weeks. After two weeks, we step out, said Sonthi, whose military Political Reform Council was legitimised by a royal proclamation.

The United States urged a quick restoration of democracy, and warned that only then would it be willing to move forward on a free trade pact. The trade deal has been under negotiation for more than two years.

We're disappointed in the coup. We hope those who mounted it will make good and make good swiftly on their promises to restore democracy, White House spokesman Tony Snow said.

U.S. State Department spokesman Tom Casey said: In light of this coup, there are aspects of our relationship that we are going to have to review, without elaborating.

British Foreign Secretary Margaret Beckett said: It's not for us to say that he (Thaksin) should be reinstalled. We have called for a return to democratic government.

Thaksin, wearing a dark suit and red tie, put his hands together in a traditional greeting as he left a Thai Airways plane at London's Gatwick Airport.

British officials said Thaksin's decision to travel to London had no political significance and noted that he had relatives in Britain.

NEW CABINET, NEW CONSTITUTION

In Thailand, the royal proclamation declared: The general public is requested to remain calm and all civil servants and state officials to follow instructions issued by General Sonthi Boonyaratglin.

The military said it acted because there was no other way out of a protracted political crisis that pitted Thaksin against the political old guard and street campaigners, who accused him of subverting democracy for his family and friends in business.

Sonthi told a news conference a new cabinet would form a special committee to draw up a new constitution and submit it to a referendum, after which new elections could be held.

It will take a year to draft a new constitution, he said.

Political reform is considered essential by Thaksin's foes to allow, they say, independent state agencies such as the election commission to be purged of his allies.

Not a shot was fired in the coup and the streets of Bangkok were quiet with very little military presence except around Government House and nearby army headquarters.

There is no threat to tourists, a Thomas Cook spokesman in Germany said of a country which draws about 12 million visitors a year.

Concerns of conflict or even a counter-coup by Thaksin's supporters appeared to evaporate and Sonthi invited the ousted leader to return, promising his assets would not be touched.

Thaksin is a Thai and a fellow countryman and there will be no problem should he decide to return. We are like brothers, said Sonthi, mostly Buddhist Thailand's first Muslim army chief.

National Police Chief Kowit Wattana said Thaksin would not face any new probes but would have to answer cases already filed, including charges of election fraud.

Leaders around the world expressed shock and disappointment at the sudden overthrow of Thaksin, whose huge popularity in the countryside gave him two landslide election wins.

The United States, European Union, Australia and New Zealand condemned as undemocratic Thailand's first coup in 15 years but its 18th since it became a constitutional monarchy in 1932.

But analysts said the coup might prove a step forward if it cleared the way out of what many saw as an intractable political deadlock threatening the stability of the nation.

This coup will be different, said Somjai Phagapasvivat of Bangkok's Thammasat University. Before, it was done in the interests of the military. This time, it was a necessary pre-emptive strike given the violent polarisation of Thai society.

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