BANGKOK--Thai Prime Minister Abhisit Vejjajiva promised on Sunday to restore law and order, and police said they had arrested a leader of the anti-government protesters who forced the cancellation of an Asian summit in the country.
In a weekly address to the nation, Abhisit said other arrest warrants were being drawn up for those responsible for the latest unrest in Thailand's long-running political crisis.
Police said they had arrested Arismun Pongreungrong, a popular singer prominent in the assault on the summit venue in the resort town of Pattaya, and were holding him at a police station north of Bangkok.
Metropolitan Police spokesman Maj-General Suporn Phansua said charges could include inciting others to break the law.
Abhisit said he had spent most of the night in meetings with senior people in the security forces.
"In the current situation, what I have to do is to bring peace to the country, bring back governance and have a process of political reform," he said.
A few hundred supporters of the United Front for Democracy against Dictatorship (UDD), which backs ex-premier Thaksin Shinawatra, ousted in a coup in 2006, demonstrated briefly at the Criminal Court in Bangkok, then moved on.
Some had said they would march on police headquarters in Bangkok, but there was no sign of any demonstration there at midday (0500 GMT) and the number of people at Government House, focus of the protests since March 26, was down sharply.
Many people have left Bangkok for the three-day Thai New Year holiday starting on Monday.
Police spokesman Suporn said 2,000 protesters were left at Government House and a Reuters reporter estimated 3,000, in either case far below the 100,000 at the high point on April 8.
Abhisit suffered a political humiliation when the summit he had presented as a sign of the country's return to normality had to be cancelled after red-shirted protesters broke into the venue, sending Asian leaders fleeing by helicopter.
"Yesterday was a truly shameful day for our country, which had its international image destroyed," the Bangkok Post said in a front-page editorial.
Thaksin's supporters say Abhisit only became premier because of a parliamentary stitch-up engineered by the army. They want new elections, which they would be well placed to win.
The events will pile more pressure on an economy teetering on the brink of recession, especially if foreign tourists are put off by the scenes of chaos.
Thai financial markets are closed until Thursday for the holiday. After months of falls, many Asian stock markets have rallied in recent weeks but the Thai market has been held back by the political unrest and is flat on the year.
Patareeya Benjapolchai, president of the Stock Exchange of Thailand, was concerned.
"It's really up to the government now how it manages the situation within this five-day break. What happened was a loss for the country. The ASEAN summit was supposed to be a step-up for our economy," Patareeya told Reuters.
Newspapers were outraged both by the pro-Thaksin supporters' insult to foreign leaders and by the government's inability to put proper security in place. Police and soldiers put up little resistance as the demonstrators marched towards the summit hotel.
"Rumors of a possible coup or House dissolution were spreading last night as it appeared the government had lacked cooperation from police and military in preventing the protesters from entering the summit venue's compound," the Nation reported.
Thaksin lives in self-imposed exile to avoid jail on a corruption conviction and is said to be bankrolling the protest.
His absence has not ended long-running political unrest, with Bangkok's royalist, military and business elite, who accused Thaksin and his allies of corruption and abuse of power, pitted against the rural and urban poor who loved his populist policies.
Thaksin phoned in to his supporters at Government House late on Saturday and, less rabble-rousing than on some occasions, thanked them for their sacrifice at this holiday time.
"If our people in Bangkok and all the provinces unite,... I think this time we can change the country. We will see real democracy with the king as the head of state," he said.