At least 22 people have been killed and a further 111 injured in an explosion produced by a fuel truck which crashed into a flyover in the Saudi Arabian capital Riyadh.

The explosion, which occurred in an industrial area in the east of the city, caused the collapse of one building and damage to several others, Saudi state television said.

Images showed the building, which spanned several stories, almost completely wiped out by the blast, with just a corner still standing amid the debris.

"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. My brother is still inside under the rubble. There are lots of people in there," a survivor told al-Jazeera.

Firefighters rushed to the scene to search for survivors in the rubble of the building and check the numerous cars set on fire by the blaze in the area.

Witnesses said the truck crashed one of the flyover's supports, but the precise cause remains unclear.

The building eviscerated by the explosion housed Zahid Tractor, a heavy machinery distribution company.