"We have taken 19 injured people and one death at our hospital," a health worker at Yala Hospital Centre told Reuters by telephone. "Most of the injured people were hit by bomb attacks," she said.
Officials ordered residents to stay at home while police tried to arrest armed men on motorcycles who shot at people and threw petrol bombs into shops in the small city of Yala, 1100km south of Bangkok.
"People should take care of themselves and just stay at home," Yala Deputy Governor Winyu Thongsakul told a Bangkok radio station.
At least eight targets were hit by attacks, which included explosions at a newly opened cinema complex and a hotel cafe, and fires at another hotel, a warehouse, and a row of shops, according to police radio heard by a Reuters reporter.
Regional army commander Lieutenant General Kwanchart Kraharn said the attacks were well-coordinated and appeared to target civilians.
"The five points where the bombs exploded are places
where people go during the night - a hotel, two 7-Elevens,
near a restaurant and near the railway station - all of
which are usually crowded with people, so we can say that
the troublemakers targeted on innocence people," he told
Thai TV Channel 5.
Chief Government Spokesman Chalermdej Jombunud said there had been at least three explosions after the blackout and police had shot and arrested one suspect.
"Road spikes were put all over the city," Chalermdej said, adding that the power had returned after about an hour of blackout and police were still hunting for culprits.
A couple of bombs had been defused and there had been some clashes between police and militants, Special Branch Police chief Prung Boonpadung said.
More than 800 people have been killed in the violence that erupted in January 2004 in the three southernmost provinces of Yala, Pattani and Narathiwat.