An explosive device injured at least 28 protesters participating in the anti-government Bangkok "shutdown" campaign Friday, hospital sources said.
The device was thrown into the midst of a march in central Bangkok being led by Suthep Thaugsuban, who has been holding street protests in the capital since early November, dpa reported.
The explosion went off about 100 metres behind Suthep, BlueSky TV reported.
"There were at least 28 people injured by the explosion," said an official at the Erawan Emergency Centre.
Since the protests began, there have been sporadic cases of violence and eight protest-related deaths.