Thailand explosion kills three in Bangkok suburb

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Media captionPolice investigate the blast in a Bangkok suburb

At least three people have been killed and nine injured in an explosion at an apartment complex in a Bangkok suburb.

Police said the blast was likely to have been caused by a large bomb, but were unable to confirm details.

There was no immediate explanation why the six-floor block in Nonthaburi province might have been a target.

Thailand has seen a string of bombings in recent months after protests failed to oust the government, and also has a long-running insurgency in its south.

Nonthaburi province is one of a number of areas of the country currently under emergency rule, imposed by the government of Prime Minister Abhisit Vejjajiva after street protests in Bangkok turned deadly earlier in 2010.

Ninety-one people died when anti-government "Red Shirt" protesters clashed with police and soldiers in capital.

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

Despite the emergency there are regular small blasts around the capital, but correspondents say Tuesday's explosion was unusually large.

"It was definitely a bomb. We cannot say what type of bomb it is yet," Major General Prawut Tawornsiri told the AFP news agency.

"But it was a massive bomb because it damaged a large area."

Early reports suggested that the blast was large enough to have been caused by as much as 50kg of explosives.

Police were assessing the building to see if it was in danger of collapsing, reports said, and were investigating whether the explosion could have been caused by explosives detonated accidentally.

"It is possible they were storing an explosive device for an operation and it exploded prematurely," Reuters news agency quoted one police official as saying.