Two of the grenades, believed to have been fired from an M79 grenade launcher, landed in the parking lot of the Thai PBS compound on Vibhavadi Rangsit Road. The blasts damaged three cars.
Two other grenades landed inside the nearby Police Sports Club, also the headquarters of the Center for Maintaining Peace and Order (CMPO). One caused minor damage, but another did not explode and was found
near the tents of riot police from Bueng Kan assigned to deal with anti- government protesters.
Police believed the grenades were launched from the elevated tollway.