
The party also denounced Somchai for pretending to be soft but authorising the use of force by police against protesters in front of Parliament on October 7.
Ong-art Klampaiboon, a Democrat MP from Bangkok, said the prime minister must take responsibility for the bloodbath caused by the crackdown and for the economic crisis stemming from the government's failure to cope with the global crisis.
Ong-art also urged Somchai to make a crucial political decision to prevent a possible coup.
The Democrat claimed that Army Chief General Anupong Paochinda had indicated a coup during an interview on Friday when the Army chief held the government responsible for the bloodbath.
He said the prime minister must urgently take responsibility before the political and economic crises escalated, and before a coup took place.
Ong-art said if the coup and the crises damaged the country, the situation would be beyond rehabilitation.
He said the prime minister had allowed his subordinates to harm the people and frame them, while setting up a panel only gives false hopes of remedy to the public.
"The prime minister pretends to be soft but his appointment of Cabinet members and his approval for use of force contradicted what he pretended to be," Ong-art said.
Democrat spokesman Buranat Samutrak said Somchai had so far failed to issue an apology to the protesters.
"The prime minister has said nothing so far to show remorse or indicate that he would take responsibility," the spokesman said.
"The prime minister and the police have declined to admit that the tear gas canisters used that day had the potential to kill."
The spokesman said Somchai pretended not to support violence but his government apparently supported the organising of government supporters to counter the People's Alliance for Democracy.
Buranat said government spokesman Nattawut Saikua had organised a gathering of over 10,000 government supporters in Bangkok on Saturday.
The spokesman also alleged that the government supported the demonstration of the Democratic Alliance Against Dictatorship at Sanam Luang yesterday to counter the PAD.