13 taken to hospitals after US apartment fire

A billowing fire engulfed a three-story building near downtown Minneapolis today morning, sending 13 people to hospitals with injuries ranging from burns to trauma associated with falls.
Officials said six of those injuries were critical, but no deaths were reported.
An explosion was reported, and within minutes a fire raged through the building, said Robert Ball, a spokesman for Hennepin County Emergency Medical Services. Paramedics responded found victims on the ground, some with injuries that suggested they may have fallen multiple stories.
"It's not clear whether people were pushed out of the building from the explosion or whether they fell or jumped out of windows to escape," Ball said.

Ball said it was too early to determine what caused the explosion or fire.
Authorities weren't sure whether any residents were still inside. Assistant Minneapolis Fire Chief Cherie Penn said the roof had partially collapsed, and it was too dangerous for firefighters to enter.

Penn said 13 people were taken to local hospitals, and six were considered to be critically hurt.
The building has a grocery store and two levels of apartments.
Firefighting efforts were being hampered by the sub-zero temperatures.