Red shirts yesterday submitted a petition seeking the ouster of the seven Constitution Court judges who ordered the suspension of parliament's deliberations of the charter amendment bill.
The petition to impeach seven of the nine judges of the court was submitted to second Senate speaker Pornthip Loweerajanratanapreeda by Tida Tawornseth and Jatuporn Prompan, co-leaders of the United Front of Democracy Against Dictatorship (UDD).
Twenty thousand signatures were collected in support of the petition.
The court had ruled 7-1 that debate on the bill should be suspended while it looked into complaints that the measure, if passed, would lay the groundwork for the future overthrow of the constitutional monarchy.
Judge Chat Cholaworn _ the only judge to vote against the suspension order _ and Udomsak Nitimontree _ who was absent during the ruling _ were spared the impeachment charges.
The Pheu Thai Party and the UDD argue the court overstepped its authority by issuing the suspension order.
They also said Section 68 of the constitution stipulates that people could not file that kind of complaint directly with the court.
About 5,000 UDD supporters gathered yesterday outside the House, accusing the court of interfering with parliament.
The rally was led by Ms Tida, Mr Jatuporn, and other UDD co-leaders such as Korkaew Pikulthong.
Hundreds of UDD supporters also gathered at city halls in many provinces _ including Pathum Thani, Chiang Rai and Surin _ to criticise the court's action.
Meanwhile, the Siam Samakkhi group urged more members of the public to come out to rally behind the judges.
Somjet Boonthanom, a senator and the leader of the group, said he would organise a seminar today at Lumpini Park to oppose the effort to amend the charter.
Gen Somjet said the event would not be an anti-government demonstration but a gathering to educate the public.
The group unveiled a video clip purporting to show a hundred young men travelling on the back of dozens of pickup trucks from Pathum Thani to Dusit Zoo near parliament early yesterday.
The group claims the men work for the Royal Forest Department and the Department of National Parks, Wildlife and Plant Conservation, and were bussed in to artificially boost the protest.
A jacket carrying the name of a national park was seen on a man on a truck before the passengers donned red shirts and joined the rally.