Three bombs planted at an irrigation site in southern Thailand blew up Friday, killing at least two people.

Police say the first two bombs detonated, killing two workers in Narathiwat province. Several others were wounded.

Officials said police responding to the scene tried to defuse a third device, but it also exploded.

The attacks wounded 13 people, including at least four police officers.

About 4,500 people have been killed in southern Thailand since Islamist insurgents began their uprising in 2004.