"A group of people came for Mor Lam," said Police Colonel Thammajak Kongmongkol, referring to traditional Issan song and dance. "They had an argument, before a person threw a hand grenade into the crowd."
Thammajak said eight people were killed and 97 injured when the M-26 grenade was hurled at the crowd just before midnight, but hospital officials treating the wounded put the death toll at seven and the injured at 111.
A nurse at Nong Bua Lam Phu provincial hospital said that most of the injured were suffering from shrapnel wounds, with none in serious condition.
Thammajak said police had started questioning witnesses who attended the temple fair to find out who was behind the bloody attack. No suspects had been arrested so far, he told AFP.