Prime Minister Abhisit Vejjajiva insists the CentralWorld shopping mall was torched on May 19 after red shirt leaders called off their rally and before troops moved into the area.
Mr Abhisit yesterday told parliament CentralWorld was set on fire several times after red shirt leaders surrendered to police during the army operation to break up the rally.
Government forces deployed for the military operation were instructed to remain where they were.
He said none of the troops had moved to CentralWorld and Siam Square, which were later set ablaze.
An investigation would be carried out to identify the details of the arson attacks on the two shopping centres and the shootings at Wat Pathumwanaram, where six people were shot dead on the night of May19.
The prime minister saw it as unnecessary for the government forces to harm demonstrators after the rally had been called off.
There were reports that fire fighters had tried to put out the blazes at Siam Square and CentralWorld but they came under fire from a group of armed men at the Siam Paragon shopping centre, he said.
Puea Thai Party MP for Bangkok Vicharn Meenchainant yesterday said the burned buildings were in areas where the military was in control.
