Five people were killed and about 60 injured in a series of six explosions in Hat Yai's business centre last night. The blasts went off at two shopping malls, one of the city's biggest hotels and three other locations.

Witnesses said the bombs went off at roughly five-minute intervals starting at around 9pm, when the area was crowded with tourists and locals going out to dine and for night entertainment.

Two of the dead were foreigners - one Chinese and one Westerner. The injured were sent to nearby hospitals including Raj Yindee Hospital, Krungthep-Hadyai Hospital and Songkhla Nakharin Hospital.

The first bomb to go off was on Thammanoon Withi Road, at the entrance to a pub called Deep Wonder in the basement of the Odean Shopping Mall. The second bomb went off at a junction a few hundred metres down the road, and the third one another few hundred metres on.

The fourth bomb went off in front of the Lee Garden Hotel, destroying tuk-tuks parked there.

The fifth explosion was at the Big C Supercentre and the last was in a restroom of a movie theatre on the fifth floor of Diana Shopping Centre.

The bombs damaged a numbers of cars and motorcycles in the vicinity.

Police said each blast had a radius of 20 metres and that they had found pieces of metal suspected to be part of the bombs.

Officials believe the bomb at the Odean Shopping Mall was planted inside a motorcycle and detonated by mobile phone. Soon after the explosions, all unattended motorcycles nearby were moved away and people were evacuated from the area for fear of more explosions.

Thammanoonwithi Road is one of the most crowded roads in Hat Yai City, with more than 10 hotels along its length. More than 1,000 tourists, both Thais and foreigners, were checked in at the hotels. All were evacuated.

Senior Police Officer Ongkorn Thongprasom said police had received reports that such bomb attacks were likely between September 16 and 20.

"After this bombing, we have to seriously discuss security measures for the area. For sure, the impact on tourism will be large," he said.

Just two weeks ago, intelligence officials predicted stronger, more vigorous attacks by militants in the deep South between September 16 and 20 since this is the week to celebrate the setting up of the Pattani Islamic Mujahideen and Pattani State.

Srisompob Jitpiromsri, an academic who studies trends in the insurgency, said after a spate of bombings in Yala two weeks ago that the insurgents would continue to "show their force" through more coordinated, simultaneous attacks.