Bloody rioting erupted in Bangkok Tuesday, with at least one reported amputation in the streets as police fire tear gas at thousands of anti-government protesters who barricaded Parliament and vowed to block the government from exiting the building.

More than 100 people were injured, including two protesters who had parts of their legs blown off by what police said were exploding tear gas canisters.

The violence, which began shortly after 6 a.m. when police first cleared the street outside parliament, surged again in late afternoon, as the authorities fired countless volleys of tear gas to break through the protesters' cordon so lawmakers could leave.

The Thai military and air force have been sent to the region to help police keep the peace in the region, but troops will not be armed, army spokesman Col. Sansern Kaewkamnerd said.

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Witnesses reported hearing gunshots, though who was firing them could not be determined. Some police had been armed with shotguns, and an AP Television News reporter saw a protester who was carrying a gun.

Rioting protesters also set fire to parked cars, trucks and vans.

About a mile away from the fighting, an unidentified person was killed when a Jeep SUV exploded near the headquarters of the Chart Thai Party, a member of the six-party coalition government of Prime Minister Somchai Wongsawat. Police said they suspected a bomb caused the blast, but could provide no other details.

Even before the violence escalated, Deputy Prime Minister Chavalit Yongchaiyudh resigned.

Chavalit, the deputy prime minister in charge of security, was seen as a key figure in helping the government to resolve the protesters' long-standing confrontation with the authorities.

"What happened was partly my responsibility in failing to resolve the conflict," he said in his resignation letter, according to Agriculture Minister Somsak Prisananantakul.

Recently-appointed Prime Minister Somchai Wongsawat was forced to sneak out of the Parliament to avoid being spotted by angry protesters demanding his resignation.

Protesters led by the People's Alliance for Democracy have occupied the grounds of the prime minister's office since late August. They expanded their protest overnight by marching to the nearby Parliament, and erected barbed wire and tire barricades to block Somchai from delivering his first policy speech to lawmakers.

Riot police moved in after sunrise and fired multiple rounds of tear gas canisters to clear a path for the government and lawmakers.

Somchai opened the parliamentary session after a 90-minute delay but as he spoke chaos escalated outside the building. Anti-government protesters regrouped and barricaded all four entrances to the Parliament, saying their goal was to block top officials from leaving the building.

Police fired more tear gas canisters to disperse a group of demonstrators armed with wooden batons and slingshots, who were throwing firecrackers at police. The opposition Democrat Party boycotted the speech.

It was unclear how Somchai left the building, but he arrived by helicopter later in the day at the Supreme Command Headquarters to meet with army chief Gen. Anupong Paochinda and Supreme Commander Boonsrang Niempradit.

Earlier in the day, spokesman Col. Sansern Kaewkamnerd said the army was "concerned" about the violence against unarmed protesters and that any serious injuries should be investigated. He dismissed speculation of a military intervention to end the unrest in Thailand, where the military has staged 18 coups since the country became a constitutional monarchy in 1932.

"Victory is near. We are surrounding the building," one of the protest leaders, Somsak Kosaisuk, told a cheering crowd outside Parliament, where protesters had chained one of the gates shut.

The unrest was the latest twist in a political crisis that has gripped Thailand for six weeks and virtually paralyzed the government.

The clashes wounded 118 people, including 24 seriously, said Petpong Kumtonkitjakarn of the Erawan Medical Center. A few policemen were among those hurt.

Somchai was sworn in as prime minister on Sept. 25 but has been forced to run the government from a makeshift office at Bangkok's Don Muang airport.

The protest alliance says Somchai is a proxy for ex-Prime Minister Thaksin Shinawatra, who was ousted in 2006 by military leaders who accused him of corruption and who now resides in exile. Somchai is a brother-in-law of Thaksin.

When protesters originally took over the grounds of Government House on Aug. 26, their intention was to oust then-Prime Minister Samak Sundaravej — whom they also accused of being a puppet of Thaksin. They later said they also opposed his successor, Somchai.

Samak was dismissed from office on Sept. 9 by a court decision that found him guilty on a conflict of interest charge.

Click here to read more on this story from the U.K.'s Daily Mail.

The Associated Press contributed to this report.