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 accidentally killed by fire from security forces, 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.
Under government rules of engagement that have been published, troops are allowed to used tear gas on demonstrators that come with 100 meters (just over 100 yards), and live ammunition on those that come within 30 meters (about 100 feet).
Thousands of anti-government protesters have brought Thailand's capital to a standstill as they seek to unseat Prime Minister Abhisit Vejjajiva's government, which they say is illegitimate and undemocratic -- accusations that Abhisit on Monday called "unfounded."
The demonstrators -- known as "Red Shirts" because of their clothing -- support Thaksin Shinawatra, who was prime minister from 2001 to 2006, before he was ousted in a bloodless coup.
More than two dozen civilians and military personnel have died since protesters began occupying key tourism and shopping areas in Thailand's capital.
The latest fighting came as the British Foreign Office warned British citizens against traveling to Thailand unless absolutely necessary, citing the ongoing political unrest there.
"This advice reflects our concern that violence could break out during the increasingly volatile political crisis," the Foreign Office said in a message posted on its website Wednesday.
Last week, the U.S. State Department issued a similar advisory for Americans.