Suspected separatist militants shot dead a Muslim couple in troubled southern Thailand Monday, while four insurgents and a villager were killed in other violence, police said. The couple was riding on a motorcycle to a food market in the troubled town of Pattani one of the worst hit areas in the Muslim-majority region -- when they were killed in a drive-by shooting, said police. Also on Monday, security forces fought a 20-minute gun battle with suspected militants during a search of a house in nearby Narathiwat province, police said. Four rebels were killed and two were arrested, while a ranger was injured, they said. In the same area, gunmen shot dead a 40-year-old Muslim villager as he walked home from a mosque after daily prayers.