Muslimske separatister antas å stå bak tre bomber som drepte ni og såret 70 i Thailand lørdag.

Three bombs went off in the business area of the city of Yala around lunchtime, they said, adding the devices may have been placed in a car and a motorcycle.

Yala Governor Detrat Simsiri told Thai television that many of the injured were hit by the third bomb, hidden in a car, as they gathered at the scene.

He later told Thai television that the situation was back to normal, but that nine people had died and 23 remained in hospital. More than ten houses had been damaged.

In Pattani province, a small bomb exploded in a food shop, slightly injuring a police officer, police said.

In a separate incident, an explosion caused a fire at Lee Gardens Plaza hotel in Hat Yai district in Songkhla province.

Some local officials attributed the explosion to a gas leak in an underground food shop but Thai media reported others as saying it could have been a bomb.

More than 300 people were hurt, most of them suffering from smoke inhalation. Channel 9 television reported five people had been killed.

The Department of Foreign Affairs and Trade says there are no reports of Australians being caught up in bomb blasts in Thailand.

A spokesman says local authorities have confirmed to the Australian Embassy in Bangkok that there are no foreigners among the dead and injured after a bomb attack in the southern town of Yala.

Nine killed, scores hurt in Thai bombings