Bangkok - Made-in-China explosive tear-gas canisters were blamed Friday for death and mayhem at an anti-government protest last week in Bangkok.

A group of policemen and their friends submitted a letter to China's ambassador to Thailand, demanding an investigation of the components of tear-gas containers used to disperse protests on October 7.

The death of two protestors and the maiming and wounding of hundreds of others have been blamed on the government. The police acted to lift a siege of Parliament by protestors attempting to prevent its formal opening under new Prime Minister Somchai Wongsawat.

A deputy leader of the ruling People Power Party (PPP), police Lieutenant Colonel Karn Tienkaew, demanded that China's ambassador explain why allegedly normal riot-control weapons turned out to be so deadly.

"The tear-gas issue must be clarified as soon as possible," Karn told the Thai News Agency. "The public is curious whether the tear gas can kill or amputate."

Earlier, the country's leading forensic investigator, Dr Pornthip Rojanasunand, said the Chinese tear gas contained RDX explosives, which appeared designed to disperse the gas after impact. Wounds on several victims appeared to have come from the gas bombs, she said.

At least two protestors lost a leg and another a hand in the clash. More than 400 people were injured, according to medical officials, with two dead. One death occurred when a pickup mysterious exploded near the protest.

Karn's move appeared designed to take some of the heat off the police and the government for the crackdown that horrified even people who were dubious about the heavy-handed actions of the protestors with the People's Alliance for Democracy, analysts said. The police have been strongly criticized for firing the tear-gas projectiles directly into crowds of protestors.

The police were themselves under attack from protestors armed with pointed sticks, slingshots and some revolvers. At least eight police officers were injured, two by gunshot wounds and one run over by a protestor's vehicle.

Three people have died and 612 injured in three violent political confrontations during Bangkok's "hot summer," according to a special government committee charged with helping victims.

The victims of the three days of violence - August 29, September 2 and October 7 - would be compensated soon, said Natthee Premrassamee, permanent secretary in the prime minister's office. A government supporter was the first to die, beaten to death by an anti-government mob.

If the Chinese embassy responds to the police request, the information would be forwarded to the protest fact-finding committee set up by the National Counter Corruption Commission at the request of opposition groups, the PPP deputy leader said.

The government is popular in the countryside but widely disliked by Bangkok elites who consider it a proxy for former prime minister Thaksin Shinawatra.

Thaksin, who was ousted in a coup in September 2006, has been charged in several corruption casts and is now seeking political asylum in London. Prime Minister Somchai is his brother-in-law. (dpa)