The explosion that rocked the Criminal Court on Ratchadapisek Road on Saturday night was from an RGD5 grenade that was hurled into the court's parking area, national police chief Somyot Pumpanmuang said on Sunday morning.
Pol Gen Somyot said he was reported that the incident occurred shortly after 8pm when two assailants arrived at the scene and one of them threw an RGD5 grenade. The explosion, however, caused no casualties.
The police chief said Russian-made RGD5 grenades had been used in a number of attacks on protesters during last year's political rallies.
Therefore, it was believed that the explosion at the Criminal Court on Saturday night, involving the same type of hand grenade, was intended to create unrest and violence to challenge the government and the National Council for Peace and Order, Pol Gen Somyot said.
Pol Gen Somyot said he had ordered police to step up security measures in cooperation with soldiers assigned for a peace-keeping mission in the capity city.
Pol Lt Gen Srivarah Rangsipramanakul, the Metropolitan Police chief, said after examining the scene of last night's explosion that military officers had taken into custody two suspects shortly after the incident.
The two suspects were being investigated, he said.
The Metropolitan Police chief also believed the incident was intended to create unrest.
As a result, stricter security measures would be taken at important government offices, he said.