BANGKOK? (UPDATE) Thai soldiers fired tear gas early Monday to disperse anti-government protesters blocking a road in Bangkok, where a state of emergency is in force, injuring at least 49 people, officials said.

The army targeted demonstrators at a major intersection, although they had not yet launched an operation against the main group of thousands of demonstrators outside the main government offices in the capital.

It came a day after Prime Minister Abhisit Vejjajiva issued an emergency decree for Bangkok and surrounding areas to curb growing protests against his four-month-old government.

"The soldiers have begun the operation to disperse the protesters at Din Daeng intersection," army spokesman Colonel Sunsern Kaewkumnerd told AFP.

"We will start with soft measures and proceed to harder ones. We will avoid loss of life as instructed by the government."

He later confirmed that troops used tear gas.

"Soldiers have fired tear gas to disperse them. More than 400 soldiers are involved in the operation," Sunsern said.

"The operation is still under way. Protesters tried to crash a car into the soldiers," he added, although this could not be independently confirmed.

Sunsern estimated there were around 300 protesters at the site. An AFP photographer at the scene and another army official said there were only about 100 protesters there.

The protesters were angry and showed a shirt covered with blood which they said belonged to one of their injured colleagues.

Emergency services said at least 49 people were injured, two of them critically, during the crackdown.

"The number of wounded rose to 49. I can confirm that there are no reports of deaths yet," Chatree Charoencheewakul, head of the national emergency medical service, told AFP.

The so-called "Red-Shirts," supporters of ousted former premier Thaksin Shinawatra, stormed a conference venue in the resort of Pattaya on Saturday, forcing the cancellation of a key summit of Asian leaders.