Panitan Wattanayagorn, a Thai government spokesman, appeared on national television on Sunday to offer condolences to the victims of the violence.

But he also denied that security forces had used live bullets during the clashes.

"There were no live bullets shot at the protesters, as far as we have evidence. There was no injury caused from live bullets from the officers," Panitan said.

"We are happy to receive more information if there is different evidence otherwise.

"As of now, we have more than 200 officers injured from the operation, 90 in serious or critical condition. We have lost four officers."

Protesters' demands

Panitan did not respond directly to the protesters' demands that parliament be dissolved.

Abhisit, who has been holed up at an army barracks, said late on Saturday that he would not bow to his opponents' demands.

"I and my government will continue to work to resolve the situation," he said in a televised address to the nation.

in depth

  Q&A: Thaksin and the red shirts
  Thailand: Warring colours
  Profile: Thaksin Shinawatra
  Al Jazeera speaks to both sides of the conflict
  Thai protesters fight for a voice
  Violence flares in the Thai capital
  Red shirts stage blood protest

Al Jazeera's Aela Callan, reporting from Bangkok, said both sides appear to be standing firm.

"It's now appearing that round two of clashes is looking almost unavoidable. It's now a battle to win the hearts and minds of the public in Thailand," she said.

"It is really looking difficult to be able to resolve this situation without some sort of political give.

"There are several scenarios that could happen now. The coalition of the government could look to dissolve the house to end the crisis. We could see troops moving on the main protest site, we may also see some kind of royal intervention."

Sean Boonpracong, a spokesman for the United Front for Democracy Against Dictatorship, which is leading the protests, said the red shirts' "morale is strong" and they would continue their fight to bring the government down.

"We are evaluating the situation and trying to organise a counterattack," he told Al Jazeera.

"What he [Abhisit] did yesterday was unacceptable. He claims that he wants to handle this in peace but clearly what the army did was fire live bullets ... what the prime minister said about the peaceful handing of the reds is simply not true," Boonpracong said.

Immediate dissolution

Sean that the protesters' original demands - that Abhisit resign and dissolve parliament in 15 days - had changed to "dissolution immediately and Abhisit must leave the country".

Saturday's violence was the worst in Bangkok since four dozen people were killed in a 1992 anti-military protest.

In video

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Red shirts remain defiant a day after violent clashes in the capital Bangkok

Washington has urged both sides to show restraint.

"We deplore this outbreak of political violence in Thailand, our long-term friend and ally, and urge good faith negotiations by the parties to resolve outstanding issues through peaceful means," Mike Hammer, a White House spokesman, said.

The Thai government said it had appointed a senior prime ministerial aide to make contact with red shirt leaders to try to find a way to halt the confrontations.

The red shirts have shown they have support among Bangkok's poor but have angered the middle classes, many of whom regard them as misguided slaves to Thaksin Shinawatra, the former prime minister ousted from power in a 2006 military coup, who is in exile to avoid a jail term for corruption.

The red shirts say Abhisit lacks a popular mandate after coming to power in a 2008 parliamentary vote following a court ruling that dissolved a pro-Thaksin ruling party.

They want immediate elections that Thaksin's allies believe they are well placed to win.