An M79 grenade was fired at the National Broadcasting Television station on Vibhavadi Rangsit road in Bangkok on Tuesday afternoon. There were no immediate reports of injury.
The grenade went off in front of the state-run broadcasting station and damaged three cars, reports said.
Police were investigating scene and initially believed the grenade was launched from the Don Muang tollway.
On March 15, an M79 grenade was fired the compound of the First Infantry Regiment on Vibhavadi Rangsit road, injuring two soldiers.