Scores of separatists launched the coordinated attacks on Monday night on facilities such as police stations, road checkpoints and schools in Yala province, provincial police chief Major General Paitoon Choochaiya said.
Early on Tuesday, two bombs rocked Yala province, slightly injuring a government official. The bombs, which were placed under cars, hit a Yala provincial education office and a car park behind the provincial hall.
Paitoon said a police officer and two suspected separatists were killed in Yala.
Earlier, authorities said five people had died in Yala and one in the neighbouring province of Pattani.
Prime minister's visit
The attacks came after Prime Minister Thaksin Shinawatra returned from a brief visit to Narathiwat province, which along with Yala and Pattani has become the scene of almost daily violence since January last year that has killed more than 1100 people.
Attacks followed a visit by Prime
Minister Thaksin to Narathiwat
Paitoon dismissed speculation that the attacks were meant as a challenge to Thaksin, who came to Narathiwat to take part in a Buddhist ceremony in which money and other support was offered to 105 Buddhist monasteries in the predominantly Muslim southern provinces.
The rest of Thailand is predominantly Buddhist, and southern Muslims complain of discrimination.
Thaksin's motorcade was forced to make a detour when security forces found a 10kg bomb planted in a tree about 200 metres from a restaurant where he had planned to eat lunch, Police Colonel Nukul Kra Kraithong said.
Bomb experts defused the bomb, Nukul said.