RIYADH – At least 10 people were killed when a fuel truck crashed into a flyover in the Saudi capital Riyadh on Thursday, triggering an explosion that brought down an industrial building, witness and television reports said.

Al Arabiya and Al Jazeera television stations said that at least 50 people were injured. Saudi Arabia's al-Ekhbariya television put the death toll at 14 and at least 57 wounded.

The Riyadh Civil Defense spokesman confirmed there were deaths from what he called a traffic accident involving a gas tanker that hit a bridge, causing a gas leak and an explosion in a nearby heavy machinery and vehicles warehouse, according to the state news agency SPA.

"The truck driver was surprised by a road accident on its route, causing it to crash into one of the pillars of the bridge," spokesman Captain Mohamed Hubail Hammadi said.

He said the incident resulted in a "number of deaths and injuries," without giving specific details.

The building, several stories high, was almost leveled by the blast, with only one corner left standing. Several adjacent buildings were damaged and nearby vehicles, including a minibus on the flyover, set on fire, witnesses said.

Television footage and pictures posted on social media showed a body lying by burnt-out vehicles and at least two charred bodies seated in a car.

More than 100 emergency personnel were combing the wreckage on the flyover and searching for victims in the rubble of the building, which housed the operations of Zahid Tractor, a distributor of heavy machinery.

"I was inside the building when the blast came. Then boom, the building collapsed. Furniture, chairs and cabinets blasted into the room I was in," said survivor Kushnoo Akhtara, a 55-year-old Pakistani worker, who was covered in dirt and bleeding from multiple cuts over his body. "My brother is still inside under the rubble. There are lots of people in there".

Saudi Arabia is still on holiday after the Muslim Eid al-Adha feast, which began last Friday.