The Thai government has extended a night-time curfew in the capital, Bangkok, and nearly a third of the country's provinces by another two days.
It was imposed last week after a long period of unrest came to an end with the military storming the anti-government protesters' camp in the centre of Bangkok.
About 50 people were killed and 400 were injured in the crackdown.
Thousands of people took part in a huge clean up drive on the streets of Bangkok on Sunday.
The BBC reports schools and government offices are expected to reopen on Monday.
Officials say they'll decide whether or not to extend the curfew on a day-to-day basis.
Foreigners involved in Bangkok arson says govt
The Thai government says two foreigners were involved in arson attacks on major buildings in Bangkok after the military forcibly broke up the protest camp of red shirt demonstrators.
Fire destroyed Thailand's biggest shopping mall, Central World, which has partly collapsed after a string of arson attacks in which 36 buildings - including the stock exchange and bank branches - were torched.
The ABC cites a government spokesman saying a white Westerner was involved in the attack on Central World, urging it to be set on fire, and that an Asian national took part in the attack on the banks.
He did not identify the foreigners, but local media have named a British man depicted on a YouTube video calling for an attack on the shopping mall. The man, who is a resident of the seaside resort at Pattaya, has denied taking part in the arson and looting.
Meanwhile, the government says red shirt protesters managed to amass a huge cache of weapons at their protest camp in Bangkok before the security forces cracked down on them this week.
Weapons shown to a group of foreign diplomats at an army camp on the northern outskirts of the city included assault rifles, hand grenades and homemade bombs.