A Thai soldier has died in Bangkok, by apparent friendly fire after clashes with Red Shirt protesters
The military police and activists faced off on a highway in the outskirts of the city as the authorities attempted to stop the Red Shirts expanding their demonstrations.
The Red Shirts later dispersed from the intersection.
Separately, a large explosion has also been heard in the Sala Daeng commercial area of Bangkok.
At least 19 other people have been injured in the clashes.
Officers fired bullets at the Red Shirts who responded by throwing stones.
Soldiers also fired into the air with automatic weapons and shotguns in an attempt to stop a convoy of up to 2,000 protesters on pick-up trucks and on motorcycles.
The Red Shirts had earlier dared security forces to try and stop them as they announced plans to widen their protest.
They had left their fortified rally base in the centre of the capital in a large convoy.
Bangkok, Thailand (CNN) -- Thai security forces fired on crowds of anti-government protesters just outside the capital, Bangkok, Wednesday as tensions flared in the latest round of confrontations between the two groups.
"This is a very tense and intense standoff," CNN's Arwa Damon reported. "There is row upon row of riot police."
Live ammunition and rubber bullets were being used by security forces, according to Damon.
The Erawan rescue agency said eight protesters were injured in the clashes. One soldier was killed by friendly fire, police said.
Riot police and government troops had massed along a major highway to stop the progress of an anti-government convoy headed toward a location where demonstrators have gathered in the past.
Security forces and riot police were trying to disperse protesters, while the demonstrators along other portions of the highway stood in the way of troop reinforcements. Rainfall cooled the conflict for a time, stopping the advance of riot police and government troops.
Thai troops and a convoy of hundreds of red-shirt protesters have clashed on the outskirts of Bangkok. One soldier has died, reportedly from a shot fired by a member of the security forces, and at least 10 people have been injured. The protesters had earlier left their fortified camp in central Bangkok to drive to a rally 50km (30 miles) away. The red-shirts, who want the government to step down, have been camped out in Bangkok for more than six weeks. Prime Minister Abhisit Vejjajiva has so far rejected their demand for him to dissolve parliament.
