At the United Nations, Secretary-General Kofi Annan said on Tuesday that military coups should not be a practice to be encouraged, referring to what had happened in Thailand.

The United Nations always supports government changes through democratic means, through the ballot box, Annan said in an interview with CNN.

In Washington, the U.S. Department of State on Tuesday said Thailand should resolve its political differences peacefully.

The United States was closely monitoring the developments in Thailand, "but the situation at the moment is unclear," State Department spokesman Gonzalo Gallegos said.

In Helsinki, Finnish Prime Minister Matti Vanhanen, whose country currently holds the rotating European Union (EU) presidency, late on Tuesday expressed grave concern over the situation in Thailand and called for immediate restoration of democratic order in the Southeast Asian country.

"It is highly regrettable that democratic institutions seem to have been taken over by military force," the EU presidency said in a statement.

Britain is also unhappy with the military coup.

"We are never happy about military attempts to overthrow a government, if that is what is happening," British Foreign Secretary Margaret Beckett said on Tuesday on the sidelines of the UN General Assembly in New York.

Earlier in London, the British Foreign Ministry said Britain was seeking more information about what was happening in Thailand, amid reports about the coup in Bangkok.

Australia is gravely concerned about at the "unacceptable" military coup aimed at overthrowing the Thai government, according to Australian, Foreign Minister Alexander Downer, who is attending the UN General Assembly in New York.

"We want to see a return to democratic rule (in Thailand)," Downer said in an interview with the Australian Broadcasting Corporation.

"It's of grave concern for us that the government has been overthrown in this way," he said.

In Wellington, New Zealand Prime Minister Helen Clark condemned the military coup in Thailand on Wednesday, saying that the country should be returned to democratic rule as soon as possible.

"New Zealand condemns any process which seeks to overturn a government by unconstitutional and undemocratic means," she said.

In Seoul, the South Korean government on Wednesday called for a peaceful solution to Thailand's political crisis.

"We hope Thailand will restore peace according to legal procedures," a foreign ministry spokesman said.

In Tokyo, the Japanese government on Wednesday urged Thailand to restore democracy.

It was "regrettable" that the armed forces had seized control of Thailand, said Japanese Foreign Minister Taro Aso in a statement.

Independent liberties organizations also responded to the coup in Thailand.

Human Rights Watch, a New York-based civil liberties group, on Wednesday urged the Thai military to restore basic civil liberties and protect those exercising their rights to free expression after the coup was staged and martial law imposed.

"Thailand needs to solve its problems through the rule of law and the people exercising their right to choose their own leaders," said Brad Adams, the group's Asia director.

Freedom House, a liberties body engaged in monitoring civil rights in Thailand since 1972, said the military coup had stalled democracy.

No group that gained power through a coup could be accepted as legitimate by democratic governments, said the group in a statement.

On Tuesday evening, the Thai military ordered tanks and troops of the Fourth Cavalry Battalion to move into strategic points in Bangkok, and seized control in Bangkok overnight as Prime Minister Thaksin was in New York for the UN General Assembly.

The military dismissed Thaksin, repealed the constitution and promised that the country would swiftly return to democracy after political reforms.