Two home-made time bombs set to explode at 9 am were found outside the Criminal Court Monday morning.
Security officials of the court found one of the bombs at a bus stop in front of the Office of Public Prosecutors Region 1 and the other outside the front wall of the court.
Traffic on Ratchadaphisek Road was closed as explosive ordnance disposal officers defused the bombs.
Police Spokesman Pol Maj Gen Anucha Ramayanon said explosives weighing about 15 kilogrammes were found in each of the fire extinguishers used to make the bombs.
Anucha said the bomb could have caused damage in a 20- to 40-metre radius.
Anucha said investigators believe the two bombs were planted by the same group of people. He said police could not yet establish the motive behind the bombs.