Thai Prime Minister Abhisit Vejjajiva said on Monday that "terrorists" were behind deadly civil unrest in Bangkok over the weekend that left 21 people dead and more than 800 injured.
"From the overall picture we clearly found that terrorists used pro-democracy protesters to incite the unrest, hoping for total change in our country," he said in a nationally televised address.
"We have to differentiate innocent people from terrorists and then we can map out further measures," he said, adding that peaceful protesters' demands for democracy should be addressed through politics.
Saturday's violence erupted when troops tried to clear one of two sites in the centre of the city which have been occupied by the "Red Shirt" protesters for the past month.
As the clashes intensified gunshots echoed around the city and both sides accused the other of using live ammunition.
Emergency services said two protesters were killed by gunshot wounds to the head.
The authorities said assault rifles and grenades were used by some people among the demonstrators.
"I didn't think among protesters there would be people using heavy weapons such as M16 and AK47 assault rifles and grenades. The military also suffered heavy losses," Deputy Prime Minister Suthep Thaugsuban told reporters.
Suthep, who is in charge of security operations, denied there was any rift between Abhisit's administration and the army, saying, "I can reassure you that there is no problem between the government and the military."
Seventeen civilians, including a Japanese cameraman, and four soldiers were killed Saturday after the army launched a crackdown on the supporters of fugitive ex-premier Thaksin Shinawatra.
Defence Minister Prawit Wongsuwon said shadowy groups were inciting unrest.
"Currently some rogue people are driving a wedge between the people and the military," he said.
"We have to take decisive action against these rogue people otherwise our country cannot survive."