Organizers of the demonstrations in the Thai capital said they’re requesting that each protester donate between two and 20 teaspoons of blood — 10 to 100 cubic centimeters — to meet their goal of more than 2,000 pints (1 million cubic centimeters). That would require between 10,000 and 100,000 people — roughly the crowd’s peak size — to donate.

“The blood will be taken from the body and democratic soul of the Red Shirts,” said a protest leader, Natthawut Saikua, referring to the popular name for the protesters. He said they would start recruiting medical staff for the blood drive Tuesday morning.

They threatened to pour the blood on Government House if their renewed demand was rejected by 6 p.m. Tuesday.

A Red Cross official expressed concern over the hygiene of drawing blood from so many people and noted that such a large quantity “could save a lot of lives,” if it weren’t destined to be spilled.

In the first reported violence of the protests, two soldiers were wounded when four grenades exploded inside the compound of the 1st Infantry Regiment, known as the King’s Own Bodyguard, said army spokesman Col. Sansern Kaewkamnerd. He did not blame the demonstrators, who were not in the area, but said there has been intelligence that some elements had been planning such attacks. The grenades were fired from an M-79 launcher, he said.

Prime Minister Abhisit Vejjajiva, the key target of the massive demonstration, earlier said he could not give in to the protesters’ demand to dissolve Parliament by midday but left room for compromise. The demonstrators marshaled around the heavily defended 11th Infantry Regiment headquarters where Abhisit has been hunkered down in recent days, but after the deadline passed they began a march back to their main encampment.

“Asking for the dissolution of Parliament before noon in exchange for a halt to the demonstrations, we all agreed it can’t be done. However, it doesn’t mean the government coalition parties and I won’t listen to their ideas,” Abhisit said on nationwide television.

The protesters believe Abhisit took office illegitimately with the connivance of the military and other parts of the traditional ruling class who were alarmed by former Prime Minister Thaksin Shinawatra’s popularity, particularly among the poor. Thaksin, who became prime minister in 2001 and whose party easily won two elections, was ousted by a 2006 military coup for alleged corruption and abuse of power.

Some 100,000 Red Shirt protesters have been camped out along a boulevard in the old part of Bangkok. A force of more than 50,000 soldiers, police and other security personnel has been mobilized in the capital area.

“Our goal is not to remain entrenched in the government.

Like all Thais, we’d like to see the country move forward,” Abhisit said. “The government must listen to the demonstrators. Although the demand can’t be met by noon, we are willing to hear what they say.”