Six explosions rocked Bangkok's financial district on Silom Road Friday as troops and protesters clashed to control the heart of the capital.
Unknown assailants fired M79 grenades at soldiers stationed at the Saladaeng skytrain station on Silom Road, Bangkok's main financial district and a popular entertainment area, Thai media reports said.
Residents in the neighbourhood said they heard six explosions.
Two people were wounded, according to The Nation newspaper's website.
The grenade attacks coincided with a military offensive against anti-government protesters who have blockaded themselves in an area around Ratchaprasong Road, a posh commercial district, just north of Silom.
At least one demonstrator was killed Friday and eight protesters and two journalists were hurt in the latest unrest, which took place after the Thai government launched an offensive the night before to drive thousands of followers of the United Front for Democracy Against Dictatorship (UDD) from Ratchaprasong.
The UDD has occupied the district since April 3, demanding that Prime Minister Abhisit Vejjajiva dissolve parliament and hold new elections.
After a peace proposal offered by Abhisit failed this week, the prime minister opted to use force to end the protests.
The UDD blamed Abhisit for provoking the violence over recent weeks, which has claimed 31 dead to date.
Last week, Abhisit agreed to hold an election Nov 14 on the condition that the UDD call off its protest.
While the UDD initially welcomed the proposal, the leadership then presented a series of additional conditions that scuttled the negotiations. Abhisit has now withdrawn the poll date.
The UDD has been staging protests in Bangkok since March 12. While the movement initially stuck to non-violent tactics, casualties started to mount after April 7 when the UDD raided parliament and the government imposed emergency law.
Since then, bloody street battles and attacks on civilians and authorities have occurred. The protest has been accompanied by more than 70 still-unexplained attacks on government targets and pro-government protesters with military weapons, such as the attack Friday night.
These unexplained attacks have given rise to theories of splits within the military or the possibility of rogue elements of former military men or paramilitary rangers operating to further their own goals in tandem with those of the UDD.
A similar grenade attack on Silom Road April 22 killed one pro-government protestor and wounded 80 others. Grenade attacks earlier this month killed two policemen deployed in the Silom neighbourhood.