Three Thai rangers were killed and five others wounded in a bomb ambush by militants in Muslim predominant restive southern province of Narathiwat, Thai News Agency reported on Thursday.

The bomb exploded in Naraathiwat's Cho-airong district on late Wednesday night as a group of 12 rangers was on patrol.

Police said the insurgents hid a home-made bomb near a lamp post in a rubber plantation and detonated it when the patrol group approached the area.

Two rangers died on the spot and the third was pronounced dead as he was rushed to a hospital. Five rangers suffered minor injuries.

Police believed the suspected separatist insurgents are responsible for the crime.

More than 5,000 people have been killed and more than 9,000 hurt in over 11,000 incidents, about 3.5 incidents a day, in Thailand's Muslim, ethnic-Malay dominated three southern border provinces -- Yala, Pattani, Narathiwat and four districts of Songkhla -- since violence erupted in January 2004, according to Deep South Watch, which monitors the regional violence.