A road crash in Algeria killed 34 people when a passenger bus collided head-on with a pickup truck carrying fuel cans and burst into flames Wednesday, deep in the southern Sahara region, officials said.

The North African country's deadliest road crash in years also left 12 others injured, many with severe burns, Algeria's civil defence agency said.

President Abdelmadjid Tebboune, on a state visit to China, expressed "his deep distress and sadness" and offered "his sincere condolences" to the victims' families.

Pictures showed the bus engulfed in a massive ball of flames that lit up the night sky after the crash around 4:00 am (0300 GMT) in a small town near Tamanrasset, a 2,000-kilometre (1,250 mile) drive south from the capital Algiers.

Later, rescue workers were seen recovering bodies from the mangled and charred hull of the bus, in Outoul, 20 kilometres west of Tamanrasset, the accident scene surrounded by fire engines.

Local residents told AFP by phone that the bus had dropped off passengers and was about to resume its journey when a Toyota pickup truck smashed into it.

National gendarmerie official Samir Bouchehit said the truck was carrying cans of gasoline and driving on the wrong side of the road.

"The first elements of the investigation suggest that the responsibility lies with the driver of the pickup, which was loaded with cans of gasoline that caught fire in the collision," he said, speaking on the private Ennahar TV channel.