Thai nationalists have begun what they call an indefinite protest in Bangkok to urge the government to take a tougher line in its border dispute with Cambodia.
At least 2,000 supporters of the People's Alliance for Democracy, also known as Yellow Shirts, gathered Tuesday on a major Bangkok street near Government House and set up an encampment with a stage, tents and other facilities.
A Yellow Shirt leader, Chamlong Srimuang, said PAD members and their allies will remain at the site until Prime Minister Abhisit Vejjajiva meets their demands. Thai authorities deployed almost 4,000 security personnel to the protest zone to maintain order.
The PAD accuses Mr. Abhisit of not responding strongly enough to Cambodia's arrest of seven Thai nationalists in a contested border region last month. The Yellow Shirts previously were supportive of the government, which is backed by the military and the monarchy.
The nationalists want the Thai prime minister to revoke an agreement with Cambodia on settling border disputes, pressure Cambodians to move out of disputed border areas, and withdraw Thailand from the U.N. cultural agency, UNESCO. Mr. Abhisit has rejected those demands as impractical.
UNESCO angered Thai nationalists in 2008 by approving Cambodia's request to grant World Heritage Status to the Cambodian-controlled Preah Vihear temple in a border area claimed by Thailand.
Thai police arrested five men Monday night on suspicion of plotting to bomb Tuesday's Yellow Shirt rally. Authorities say the suspects were in possession of weapons and explosives. The identities of the men were not revealed.
Bangkok has seen a series of prolonged and sometimes violent street protests in recent years by the Yellow Shirts and their arch-rivals, the Red Shirts. The Red Shirt movement is composed of mostly of rural and working class supporters of former prime minister Thaksin Shinawatra, ousted by the military in 2006 for alleged corruption.
Red Shirt activists staged a major anti-government rally in Bangkok Sunday, drawing almost 30,000 people.