A bomb victim is rushed to Yala Hospital. Left: A police officer checks for evidence after defusing a bomb in a Yala department store toilet.

A string of coordinated bombings and arson attacks hit more than 30 targets, including a power plant, in the southernmost provinces last night, causing a widespread blackout and killing at least three people, security officials said.

At least two people were killed and 29 injured in the Betong and Muang districts of Yala in a series of raids that also targeted karaoke bars and petrol stations.

Yala was the worst affected province in the latest violence, said army spokesman Col Akara Thiproj, as 24 bomb blasts spread chaos and confusion around the province.

Other bombings and arson attacks took place in Pattani, Narathiwat and Songkhla provin-ces, police said.

In Pattani a bomb struck a power plant in the Muang district at about 7pm leaving most of the province in darkness. The police and military were attacked in other districts but the police reported no casualties.

In Narathiwat, six bomb attacks hit various targets, including a karaoke bar in Sungai Kolok district at 8.45pm. One man was killed and about 20 injured in the incidents. Arson attacks were also reported at schools and a mosque in the province's Sungai Padi and Rusoh districts, officials said.

In Songkhla, a number of arson attacks took place in Jana, Na Tawee and Saba Yoi districts. Details about property damage and casualties were unknown, police said.

Among the targets hit by last night's Yala blasts were the My Way and Wang Mai karaoke bars, two petrol stations and the Coliseum department store.

Earlier yesterday, two bombs were discovered in toilets at a busy department store in Yala's Betong district. They were defused.

Cleaners at the Betong Plaza department store on Sukayang Road found the packages that each contained three kilograms of explosives.

A bomb team from the Betong border patrol took 10 minutes to defuse the bombs.

The explosives were placed in tin boxes and would have been detonated using a digital wristwatch.

Investigators believe the thwarted attacks were the work of insurgents and were carried out in response to the earlier arrests of four suspects in connection with a string of bombings at banks on August 31 last year.

Army Commander-in-Chief General Sonthi Boonyaratglin said last night security officials had received intelligence reports  more attacks were imminent in the four southernmost provinces but could not immediately pinpoint the targets.

Sonthi said he has ordered additional troop deployment for the areas hit by the bomb attacks and their vicinity but still saw no need to declare a curfew or a state of emergency.