NARATHIWAT (Thailand) - TWO bombs planted by suspected separatist insurgents have killed one person and injured nine others in the Muslim-majority south of Thailand, police said on Friday.

A 20-year-old man was killed and two others including a policeman injured by a bomb planted in a motorcycle on Thursday evening in Narathiwat, one of three southern provinces badly hit by a five-year-long insurgency.

Also in Narathiwat a day later, a powerful car bomb injured four policeman and three civilians.

Police said 40kg of explosives were packed in a car parked by a train station and detonated by mobile phone, but the police escaped death as they were travelling in an armoured vehicle.

Thailand's troubled south marks the five-year anniversary of the start of the insurgency on Sunday, and militants have increasingly been employing sophisticated technology such as car bombs to target authorities.

More than 3,500 people have been killed since separatist unrest erupted in January 2004. Tensions have simmered since Thailand annexed the mainly Malay sultanate in 1902. -- AFP