Thaksin is living outside Thailand, but is still the focus of the protests
Thailand's government has revoked all the passports held by ex-prime minister Thaksin Shinawatra in the aftermath of the protests that paralysed Bangkok.
It leaves the exiled former leader without any legal travel documents.
An arrest warrant has also been issued for Mr Thaksin, who has been calling for a popular uprising in Thailand.
Bangkok is now calm, after clashes between troops and anti-government protesters. Fights were also reported between residents and protesters.
At least two people were killed and more than 100 injured in the violence.
On Wednesday, Mr Thaksin published a statement calling on his followers to pursue their struggle through peaceful means.
He blamed Monday's violent scenes in the capital solely on the government's decision to deploy the army against his red-shirted supporters.
The decision to revoke Mr Thaksin's personal passport also follows the recent disruption of a major Asian summit by his supporters. His diplomatic passport was invalidated in December.
A government spokesman said that if a person was "doing anything that could undermine the security of the nation, then we have the right to revoke the passport".
A state of emergency is still in force, but the streets are quiet
The BBC's Jonathan Head in Bangkok says the move leaves the exiled former leader with no legal travel documents - unless he can persuade another country to give him asylum.
Until now he has been living mostly in Dubai, but it is not clear what his status there will be now he has no passport, our correspondent says.
The government says it has been in talks with other countries and Interpol to try to get him sent back to Thailand, where he has been sentenced to two years in prison for abuses of power when he was in office.
He now also faces additional charges of inciting a public disturbance - for which an arrest warrant was issued by the authorities on Tuesday in the wake of the protests.
Police are still hunting 10 key protest leaders, after three others surrendered.
Prime Minister Abhisit Vejjajiva welcomed the end of the protests on Tuesday, but said his government would remain on guard.
He is now working from a secret location because he fears an assassination attempt, our correspondent says.
Mr Abhisit has accused Mr Thaksin's supporters of stockpiling weapons for a possible armed struggle against the government.
During the three-week-long rally, Mr Thaksin addressed the red-shirted protesters nearly every night via a video-link. In one speech, he called for a "revolution".
The protests shut down large parts of Bangkok, as the demonstrators called for the current government to step down and call fresh elections.