Relatives hold pictures of victims during a memorial service for those who died in Saturday night's clash near Democracy Monument. ((Vincent Yu/Associated Press))

Leaders of Thailand's anti-government protests on Sunday rejected a government overture to hold talks to end demonstrations that have escalated into deadly confrontations.

Protesters remained on the streets of Bangkok, a day after the country's worst political violence in nearly two decades.

The death toll following clashes with soldiers rose to 21, with nearly 900 wounded early Sunday, after a night of gasoline explosions, gunfire and tear gas, ending four weeks that were relatively calm.

Government spokesman Panithan Wattanayakorn said the government's objective was to avoid more violence and "to return the city to normal," but indicated there was no clear solution.

Jatuporn Prompan, one of the leaders of the so-called Red Shirts, said there would be no more negotiations with the government of Prime Minister Abhisit Vejjajiva.

He said at this time, his side has a "duty to honour the dead," by bringing democracy to Thailand.

Protesters held a procession for the dead Sunday near their rally site in historic Bangkok. Marching with Buddhist monks, they held aloft several coffins and carried photos of the victims.

One mother called her son "a hero" before breaking down in tears.

Protesters show off seized weapons

Earlier, protesters showed off a pile of weapons they had captured from the troops, including rifles and heavy calibre machine-gun rounds.

More than half a dozen military vehicles, armoured personnel carriers, Humvees and a truck were crippled by the protesters, who ripped the treads off the armoured cars.

The Red Shirt movement contends that Abhisit came to power illegitimately in the years after former prime minister Thaksin Shinawatra was removed in a 2006 coup amid corruption allegations.

The demonstrators have sworn not to let up their pressure until Abhisit steps down and calls new elections.

Abhisit has offered to call elections by year's end, but the protesters want quicker action.

With files from The Associated Press