The premier has ordered police and National Intelligence Agency to probe into the triple explosions in Klongton district on Tuesday, Thitima Chaisang, deputy PM's secretary general said.
Foreign Ministry is assigned to talk to Iran as a suspect seriously injured in the blast was believed to be an Iranian.
Pol Maj Gen Wichai Sangprapai, deputy metropolitan commissioner was quoted as saying the suspect and two other Iranians rented a house in Soi Pridi Panomyong 31 for months.
The house was suspected to where the bombs were made. However the explosives went off this morning in the house, sending to the three to flee.
Two of them managed to escape while the suspect followed them.
A taxi refused to pick up the suspect who was covered with blood from the blast, so he threw a bomb at the driver, damaging the vehicle. The suspect then walked away and threw the bomb at a police officer who tried to stop him.
However the bomb fell to the ground and went off, mutilating his legs.
Police are now hunting for the fleeing two Iranians.
Meanwhile Opposition leader Abhisit Vejjajiva said security authorities should intensify their measures as the situation was still fragile.