Aware that parties allied to Thaksin are likely to win any election under present arrangements, the protesters want political reforms pushed through before any vote.

Twenty-three people have died in political violence since late November. Heightening the risk of further strife, the pro-Thaksin "red shirt" movement got a new, more militant leader at the weekend and he promised to lead supporters into the streets to save Yingluck if the courts ousted her.

Gunmen attacked the Bangkok home of the new leader, Jatuporn Prompan, and that of a fellow red shirt leader, Nisit Sintuprai, on Wednesday. No one was hurt in the attacks, said Thanawut Wichaidit, a spokesman for the movement.

Among the charges Yingluck faces is one of dereliction of duty brought by the National Anti-Corruption Commission over a ruinous rice subsidy scheme. She has been given until March 29 to defend herself.

Some analysts say she faces an uphill task in a legal system stacked with anti-Thaksin appointees.

"The judiciary is strongly anti-Thaksin ... Judges were chosen after the coup (in 2006) based upon proven anti-Thaksin credentials," said Paul Chambers, director of research at the Institute of South East Asian Affairs in Chiang Mai.

"The Constitutional Court has almost never ruled in favour of pro-Thaksin political parties."

Thai government to lift Bangkok emergency	Policeman and protester killed in Bangkok clashes