Protesters scuffle with riot police as they pour human blood in front of the Democrat Party headquarters in Bangkok on Tuesday. (Sukree Sukplang/Reuters) Thai protesters poured donated blood outside the front gate of the government headquarters in Bangkok on Tuesday in a symbolic move to press their demand for a new election.

Thousands of protesters volunteered to have small amounts of blood drawn by nurses. The blood was transferred into dozens of large plastic water jugs that were passed through the crowd of cheering protesters before being delivered to Government House, the prime minister's office.

Police allowed protest leaders to approach the white iron front gate and pour the blood, which oozed under the gate as national television broadcast the images live.

A Buddhist monk donates blood as supporters of former prime minister Thaksin Shinawatra gather in Bangkok to demand a new election. (Sukree Sukplang/Reuters)Prime Minister Abhisit Vejjajiva has not entered his office at Government House since the protests started on Friday.

"The blood of the common people is mixing together to fight for democracy," Nattawut Saikua, one of the protest leaders, told cheering supporters.

"When Abhisit works in his office, he will be reminded that he is sitting on the people's blood."

Not all the blood was spilled immediately, and protest leaders said the rest would be poured outside the headquarters of the ruling Democrat Party and the prime minister's house if their demands were not met.

The Red Shirts include supporters of former prime minister Thaksin Shinawatra and other activists who oppose the 2006 military coup that ousted him for alleged corruption and abuse of power.

They believe Abhisit came to power illegitimately with the connivance of the military and other parts of the traditional ruling class who were alarmed by Thaksin's popularity.

On Monday, thousands of protesters departed from their encampment in downtown Bangkok to besiege an army base on the edge of the capital where Abhisit has partly been based during the protests.

Abhisit told a nationwide television audience that his government's goal is not to "remain entrenched" but that it would not step down in response to the protesters. He said the government would listen to the demonstrators.

Embassies urge caution for travellers

The protests have to date been remarkably peaceful, although a number of embassies have issued warnings to their nationals of possible violence around Bangkok, and U.S. Assistant Secretary of State Kurt M. Campbell cancelled a scheduled visit Tuesday.

The U.S. Embassy said Campbell, on a swing through Asia, skipped the trip since he did not wish to add to "logistical burdens facing our Thai friends at this time."

Canada's Foreign Affairs Ministry "strongly advised" travellers to avoid protest sites and prominent government buildings in Bangkok, including Government House and the parliament building.

Thailand has been in constant political turmoil since early 2006, when anti-Thaksin demonstrations began. In 2008, when Thaksin's political allies came back to power for a year, his opponents occupied the prime minister's office compound for three months and seized Bangkok's two airports for a week.

With files from CBC News