A bomb ripped through an apartment complex on the outskirts of Bangkok yesterday, killing at least three people, police said, hours after authorities prolonged a controversial state of emergency.

The blast – believed to have occurred in a room on the second floor of the residential complex in Nonthaburi Province north of Bangkok – shattered windows and damaged nearby buildings.

“It was definitely a bomb. We cannot say what type of bomb it is yet ... But it was a massive bomb because it damaged a large area,” said national police spokesman Major General Prawut Tawornsiri.

“We have found three bodies at the scene, but (the death toll) could be more. We had to stop searching as we’re afraid that the building may collapse,” he said.

It was unclear whether the blast was planned.

The explosion came hours after Thailand extended a state of emergency in Nonthaburi and three other provinces, including Bangkok, for three more months.

The emergency laws were introduced in the capital in early April in response to mass anti-government rallies by the “Red Shirt” movement that ultimately left 91 people dead in clashes between demonstrators and the army.

The rules ban public gatherings of more than five people and give security forces the right to detain suspects for 30 days without charge.