Tens of thousands of Thai protesters have rallied in their latest attempt to oust the prime minister, paralysing central Bangkok and vowing to block parties from registering for hotly disputed polls in February.
The protest on Sunday followed a declaration by the main opposition Democrat Party that it would boycott a snap election called by embattled Prime Minister Yingluck Shinawatra for February 2.
At least 150,000 people had gathered at several sites across Bangkok by Sunday evening, National Security Council chief Paradorn Pattanatabut said.
Firebrand protest leader Suthep Thaugsuban, who has vowed to destroy the "Thaksin regime", dismisses Yingluck's call for an election, saying it will install another Thaksin-allied government.
Addressing a crowd of tens of thousands at the city's Democracy Monument, Suthep urged protesters to blockade the site where the Election Commission is due to hold party registrations from Monday.
"Whoever wants to go inside to register will have to pass through us," he said. "If we do not hold the country by February 2, we will shut the country down. No one will go to vote," he added.
"We will take our country back from the hands of the Thaksin regime," Suthep said.
Al Jazeera's Jonathan Gravenor, reporting from Bangkok, said anti-government protesters have shown "stamina and the ability to organise."
"At each location they have been able to set up an elaborate stage and bring in tens of thousands of people," he said. "But the question is, is the government listening?"
Thailand has lurched deeper and deeper into crisis despite Yingluck's attempt to dissipate the unrest by calling an election.
Demonstrators want to rid Thailand of Yingluck and the influence of her Dubai-based brother Thaksin -- an ousted billionaire ex-premier who is despised by a coalition of the southern Thai poor, the Bangkok middle classes and the elite.
The self-proclaimed People's Democratic Reform Committee is calling for an unelected "people's council" to be installed to oversee sweeping but loosely-defined reforms before new elections in around a year to 18 months.
Earlier several thousand people -- mainly women -- gathered outside Yingluck's suburban house amid tight security, although the premier was travelling outside the capital.
Blowing whistles -- the symbol of the weeks-long protests -- and waving Thai flags, the crowd chanted "Yingluck get out!"
The premier, who was forced to dissolve parliament in early December after the Democrat Party resigned en masse from parliament, is in the northeast of the country -- the heartland of her ruling party.
Analysts said Suthep's bid is backed by powerful behind-the-scenes forces in a country which has seen 18 successful or attempted coups since 1932.
His movement was bolstered Saturday by the Democrats' announcement of a poll boycott.
The move dismayed the prime minister, who said elections must take place to secure Thailand's fragile democracy.
"If we don't hold on to the democratic system, what should we hold on to?" she told reporters Sunday.
"If you don't accept this government, please accept the system," she said, adding elections would allow protesters to be heard at the ballot box.
Suthep led a boisterous march of several thousand people to Bangkok's main commercial district, as demonstrators blocked traffic at several points across Bangkok -- including at a symbolic intersection occupied by rival "Red Shirts" in 2010 pro-Thaksin rallies which ended in bloodshed.
Suthep, who was then deputy prime minister for the Democrat Party government, faces murder charges over the crackdown, which left scores dead.
Democrat leader Abhisit Vejjajiva has also been indicted for murder over the crackdown.
The Democrats have not won an elected majority in some two decades. Their party previously boycotted elections in 2006, helping to create the political vacuum which heralded a military coup that ousted Thaksin.