A bomb planted in a dirt road has killed six soldiers in southern Thailand, in what apparently was an attack by Muslim separatists in an insurgency that has cost more than 6,500 lives since 2004.

Police Major Pompetch Chotiklang said the explosion Monday in Pattani province also wounded four other soldiers and blew the truck they were travelling in into pieces, with parts of it landing 100 meters (yards) away.

The separatists are mostly active in Thailand's three southernmost provinces of Pattani, Narathiwat and Yala, the only ones with Muslim majorities in the Buddhist-dominated country.

Police say there is usually an upsurge in attacks during the Muslim Holy Month of Ramazan, which this year began on May 26 and ends on June 24 in Thailand.