Jiradet said Islamic insurgents were suspected of carrying out the bombings.
Later in the day in the same province, suspected insurgents staged drive-by shootings, killing four villagers riding on motorcycles, said Jiradet and other police officials.
Another attack occurred in Pattani province, where suspected insurgents on motorcycles fatally shot a 35-year-old farmer on a roadside in Panarae district, said police Col. Manit Yimsaai.
More than 5,000 people have been killed in predominantly Buddhist Thailand's three Muslim-dominated southernmost provinces since an Islamic insurgency erupted in 2004.
The regular attacks in the sub-region, with security officers as one of the main targets, are seen as a hindrance to the Thai government's attempt to revive peace talks with the Muslim militants after both sides signed a breakthrough deal in February, agreeing to hold discussions to ease nearly a decade of violence. New talks have repeatedly been postponed since insurgents in August accused the government of failing to respond to their demands.