BANGKOK — Around 100,000 protesters converged in Bangkok Sunday to give Thailand's military-backed government an ultimatum: either call elections or face more pro-democracy demonstrations over the coming week.
The demonstrators, popularly known as the 'Red Shirts,' want Prime Minister Abhisit Vejjajiva to call new elections, which they believe will allow their political allies to regain power. They believe Abhisit came to power illegitimately with the connivance of the military and other parts of the traditional Thai ruling class who were fearful of former Prime Minister Thaksin Shinawatra's popularity while in office from 2001 until he was ousted in a 2006 coup.
"We're demanding the government give up the administrative power by dissolving the Parliament and returning power to the people," a protest leader, Veera Musikapong, told a sea of red-shirted followers. "We're giving the government 24 hours from now (to respond to our demand)."
The crowd estimated by police at more than 100,000 rallied peacefully under a blazing sun. Loud pop music and rural delicacies such as spicy papaya salad competed with fiery rhetoric for their attention.
Bangkok's notorious traffic was light and businesses were shuttered as many citizens feared a repeat of past violence during the four-day demonstrations, which officially began Sunday but have been building for two days as caravans of protesters poured into the city. The demonstrators stress they will use only peaceful means.
An intelligence source said the government was considering invoking emergency law if the situation gets out of control, the Bangkok Post reported.
Protest leaders plan to maintain pressure on Abhisit to dissolve parliament and call an election Thaksin's allies would be well placed to win.
"If Abhisit does not quit by Monday, we will march all over Bangkok," said Veera Musikapong, chairman of the protest group, the United Front for Democracy against Dictatorship.
Abhisit's government must go to the polls by the end of next year, and is unlikely to agree to immediate elections.
Thailand's security forces were on their highest alert, said Thawil Pliensri, secretary general of the National Security Council, told Reuters.
"It may get more volatile after a few days as the protest leaders step up their measures and people are tired and frustrated. We have to make sure there is no damage."
The protests add a new chapter to a seemingly intractable political crisis broadly pitting the military, urban elite and royalists, who wear the revered king's traditional color of yellow at protests, against the mainly rural Thaksin supporters.
The protesters say the British-born, Oxford-educated Abhisit came to power illegitimately, heading a coalition cobbled together by the military after courts dissolved a pro-Thaksin party which led the previous coalition government.
Crowds gathered under tents and umbrellas, sitting on plastic sheets and mats listening to speeches and folk songs on stage.
"This government angers me. I never cared much about politics until a few years ago when it becomes so clear they are trying to hold onto power at the expense of people like us," said Teerachai Sukpitak, a farmer from northeast Leoi province.
The protesters chafe at what they say is an "unelected elite" preventing allies of twice-elected Thaksin from returning to power through a vote. Adding to their anger, Thailand's top court seized $1.4 billion of his assets last month , saying they were accrued through abuse of power.
"We are here to ask for justice and for rule of law to be applied to all," one protest leader, Weng Torirajkan, told cheering supporters.
"Since the government cannot do it because it's too busy serving the elite, we ask that it step out and call fresh elections so we have a government that represents the whole country, a government that represents us."
Thailand was plagued by political upheaval in 2008 when yellow-shirted protesters who opposed Thaksin's allies in the previous government occupied the prime minister's office for three months, and then formed a blockade at Bangkok's international airport until a court ousted the government.
Thaksin, a 60-year-old former telecommunications tycoon, has lived in self-exile mostly in Dubai since he was sentenced to two years in prison in 2008 on graft charges. He spoke to supporters by video link from an undisclosed location in Europe late on Saturday, urging them to rally together to topple the government.
"Keep good health, be patient and stay strong," he said. "The more they bully me, the more I will fight."
He is beloved in the vote-rich north and northeast after becoming the first Thai leader to win election twice, both in landslides, largely by reaching out to the poor through unprecedented populist policies such as universal healthcare.
His critics accuse him of authoritarianism, corruption and undermining the monarchy.
Soldiers stood at many state buildings after government warnings of potential sabotage, including bombings and arson.
Roberto Herrera-Lim, an analyst at Eurasia Group, said the Red Shirts recognized violence would be counter-productive and were now intent on building up public support.
"Whether the Red Shirts will accomplish anything at all depends on the numbers that they can muster," he said.
Reuters and The Associated Press contributed to this report.