Two people were killed and dozens more were injured Monday when an explosion sent flames shooting into the sky from a Bologna-area highway overpass, causing a bridge to partially collapse, Italian police and media reported.

Police said up to 70 people were injured when a truck carrying flammable cargo exploded after a traffic accident in Borgo Panigale, located on the outskirts of Bologna.

Some of those injured suffered serious burns while others were hit with flying glass when windows shattered in nearby buildings.

Officials did not immediately know what kind of explosives were in the tanker, but the news agency ANSA said liquefied petroleum gas was in the truck when it collided with another tanker truck just before 2 p.m., reports said.

Fireball-like flames and thick black smoke were seen near the Bologna airport. Flames from the overhead highway fell to the lower level, setting the vehicles below on fire and causing a second explosion.

A bridge that overlooks the Via Emilia also partially collapsed. Authorities closed the highway in both directions as firefighters work to put out the fire. A gaping hole was seen in the raised highway next to the tanker.

The Associated Press contributed to this report.