Two anti-government protesters were killed and 21 were wounded in a gun and grenade attack in Bangkok,
medical officials and police told AFP news agency, stoking fears of wider political violence in the crisis-hit kingdom.
Police said two M79 grenades were launched into a protest site at the city's Democracy Monument early Thursday and were followed by gunshots.
"The first victim was a protester who was sleeping at Democracy Monument, while the second victim was a protest guard who died from gunshots," Police Major Wallop Prathummuang told AFP.
In a statement on its website, the city's Erawan Emergency Centre said two people were killed and 21 wounded, without giving further details.
The deaths take the toll from six months of protests aimed at toppling the government to 27, with hundreds of others wounded in gun and grenade attacks linked to rallies.
Anti-government protesters have moved to the area immediately around Government House in the city's historic quarter as they try to press the Thai Senate to remove the caretaker administration and appoint a new prime minister.
Former premier Yingluck Shinawatra was ousted by a Thai court last week, but was swiftly replaced by the ruling Puea Thai party, who are refusing to bow to pressure saying they are the democratically elected government.