Anti-government demonstrators call out former Thai Prime Minister Thaksin Shinawatra's name during a rally in Bangkok on Thursday. (David Longstreath/Associated Press)

Thailand's prime minister says the government is willing to hold talks with activists who have been demanding new elections, but only if they stay peaceful and stop tossing donated blood at government buildings.

Tens of thousands of protesters have converged in Bangkok in recent days to demand that Prime Minister Abhisit Vejjajiva call new elections. Abhisit has refused, prompting the demonstrators to step up their protests.

On Wednesday, about three dozen red-shirted protesters tossed bags full of blood, donated by supporters, at the prime minister's private home. Another group of demonstraters splattered blood across government offices a day earlier.

The demonstrators believe Abhisit came to power illegitimately with help from the military and other parts of the traditional ruling class, and that only new elections can restore integrity to Thai democracy.

PM blasts protesters' tactics

Abhisit said Thursday that the government would tolerate the protests as long as they stay peaceful, but he also expressed frustration with the demonstrators' tactics.

"If demonstrators follow the rules, the government sees no problem in talking," Abhisit told a televised news conference from the army base, which is also serving as a temporary seat of government.

The blood-spilling tactic — said to show the willingness of the common people to sacrifice themselves for their cause and their nation — grabbed attention, but put the Red Shirt movement no closer to its goal of forcing new elections.

"Actions like drawing blood, pouring it and throwing — strictly speaking are not all legal," Abhisit said, adding that protesters were also not allowed to block city streets and prevent government employees from entering their offices.

Protesters support ex-PM

Abhisit said some protesters who hurled blood at his home Wednesday reportedly shouted if he had been inside, they would have taken "the blood from his head to wash our feet.

"That doesn't reflect a non-violent approach," said Abhisit, who has been sleeping at a government base outside Bangkok to avoid protesters.

Most of the protesters are supporters of former prime minister Thaksin Shinawatra, who was ousted by a 2006 military coup for alleged corruption, and pro-democracy activists who opposed the army takeover.

Leaders of the movement, formally known as the United Front for Democracy against Dictatorship, said they are organizing a major protest that will pass through the streets of Bangkok on Saturday.

More than 100,000 demonstrators converged on the capital Sunday, and organizers boasted that they would topple the government within days. But the crowd shrank Wednesday to around 40,000, according to Maj.-Gen. Vichai Sangparpai, a metropolitan police commander.

With files from The Associated Press