Thailand's military rulers said Tuesday they wrote a temporary constitution appointing themselves advisers to any interim government, and hinted they might replace ousted premier Thaksin Shinawatra with an ex-military man.

The comments by coup leader Gen. Sondhi Boonyaratkalin gave the first indication that military rulers who seized power a week ago do not plan to withdraw entirely from the political process -- a prospect that critics condemned as another blow to democracy.

CountryWatch: Thailand

Sondhi told reporters the draft constitution will be reviewed by academics and submitted to the king for a royal endorsement by Sunday, at which point a new leader can be named.

The ruling military council hopes to install a new civilian prime minister "as soon as possible," but is still narrowing down its candidates for the job, Sondhi said. He did not rule out a former soldier for the temporary role.

"When you say 'civilian prime minister,' you will see that soldiers after they retire can be called civilians," Sondhi said in a response to a question during a nationally televised press conference.

Sondhi led a coup that ousted Thaksin on Sept. 19 and said at the time that a civilian leader would be installed within two weeks -- or by Oct. 4.

But on Tuesday he said the military council -- formally called the Council for Democratic Reform under Constitutional Monarchy -- will stay on in an advisory role after it hands over power to a civilian government.

Under the temporary constitution the ruling council will be "transformed" into the National Security Council, to advise the government on security matters, Sondhi said.

"We do not know what the internal situation will be in the future," Sondhi said. "As of today the situation is calm, orderly and peaceful, but we do not know what is going to happen in the future."

Democrat Party leader Abhisit Vejjajiva said the coup makers appeared to be backtracking on promises to quickly step aside.

"If they hold on to power, it will be the opposite of what was announced and we hope that it will not happen," he said.

Democracy activist Ji Ungpakorn, a political science professor at Chulalongkorn University, said that any interim government not elected by the people was unacceptable -- whether the person is an ex-soldier or civilian.

"It doesn't really matter who the prime minister is," he said. "A military appointed government has no legitimacy."

The military council has said it wants a constitution with less "loopholes" that makes future leaders more accountable. Sondhi said Tuesday that a draft interim constitution has been written and will be submitted for endorsement by Thailand's king by Sunday.

Sondhi said the incoming prime minister must be someone "well accepted by society" who is honest and "able to create unity" in the country.

He said the new prime minister will have a free hand to choose ministers for a 35-member Cabinet.

One of the leading candidates for the job is believed to be former army commander Surayud Chulanont, who is a member of the king's inner circle of advisers.

Others appear to be a high-court judge, Supreme Administrative Court President Ackaratorn Chularat; Supachai Panitchpadki, a former head of the World Trade Organization and a current U.N. official; and Pridiyathorn Devakula, chief of Thailand's central bank.

All are regarded as corruption-free and either politically neutral or on record as having opposed Thaksin's regime.

Moves to oust Thaksin -- who overwhelmingly won three election victories since 2001 -- began earlier this year when tens of thousands of people took to the streets of the capital Bangkok accusing him of corruption and abuse of power, and calling for his resignation.

Since taking power, the military council has established several anti-corruption panels to investigate accusations of wrongdoing against the Thaksin government.

The military has cited official corruption as one of the reasons for its Sept. 19 coup, staged while Thaksin was attending the annual U.N. General Assembly meetings in New York.

The top graft-fighting panel said Monday it might freeze the assets of Thaksin and his top aides if evidence is found that they tried to transfer their wealth abroad. Thaksin is currently in London.

Sondhi said he did not expect Thaksin to return home anytime soon.

"I think he is aware of the situation," Sondhi said. "I do not think he will return in the near future."

Thaksin's family is one of the wealthiest in Southeast Asia -- and was even before he became prime minister in 2001.

The military council has also promised to hold elections by October next year after a new constitution is enacted to replace the one scrapped when it ousted Thaksin.

CountryWatch: Thailand