RENO, Nev. (AP) — Two people died in an early morning house fire in Reno on Friday, fire officials said.

Two other occupants already had escaped unharmed when firefighters arrived at the two-story house in flames in a south Reno neighborhood just before 3 a.m. Friday, the Reno Fire Department said in a statement.

A man and a boy were taken to a local hospital where they were pronounced dead. The victims’ names have not been released.

One firefighter also was taken to a local hospital with burn-related injuries. Other firefighters were treated at the scene for minor issues stemming from the blaze, the department said, but no information was released about their conditions.

“The fire was extremely intense and spread quickly, resulting in extensive damage to the structure and partial collapse of the roof. Ultimately, firefighters were able to locate and remove both victims from the structure,” the department said.

The cause of the fire remains under investigation. Anyone with information was asked to call the Reno Fire Department at 775-334-2300, or call or text Secret Witness at 775-322-4900.