A 49-year-old railway security guard was shot dead in troubled Yala province in a drive-by shooting as he left his house late Saturday morning, they said.

Later the same day a small bomb hidden inside a motorcycle and triggered by a mobile phone, detonated in front of a convenience store in nearby Pattani province and injured eight people including two children and two policemen.

One of the injured, a woman, later died in hospital.

Meanwhile, another small bomb, hidden inside a pick-up truck, was set off in front of a Yala hotel, injuring four slightly.

More than 3,500 people have been killed since separatist unrest erupted almost five years ago in Thailand's Muslim-majority south.

Tensions have simmered since Thailand annexed the mainly Malay sultanate in 1902. -- AFP