Suspected separatist militants have shot dead five Muslim civilians in Thailand's restive south, police said Saturday. Gunmen entered the home of a 51-year-old man and shot him dead late Friday in Yala province, one of three troubled provinces in the far south. Police said the man had been working as a government informant. Two other men, aged 18 and 34, were also shot and killed in neighbouring Pattani province, while a 61-year-old man was killed in a drive-by shooting as he travelled to Friday prayers at a local mosque. A 31-year-old farmer was also shot dead in an ambush in Narathiwat province as he returned home from work. More than 3,600 people have been killed and thousands more injured in five years of separatist violence in the Muslim-majority provinces near the Malaysian border. Buddhist-majority Thailand annexed the ethnic Malay area in 1902, sparking decades of tension and mistrust.