At least 20 people are now known to have died in clashes between Thai troops and opposition supporters in Bangkok, and more than 800 were hurt.
The worst violence came when soldiers and police made an unsuccessful attempt to retake an area held by opposition supporters on Saturday evening.
They fired tear gas and rubber bullets while protesters hurled petrol bombs, in the deadliest violence in 18 years.
A government spokesman denied reports that live rounds had also been fired.
“There were no live bullets fired at protesters,” Panitan Wattanayagorn said on national TV, AFP agency reported.
At least four soldiers were among the dead on Saturday.