Authorities in Waltham say two people have died and a firefighter has been injured in a house fire.

The Fire Department says the fire broke out at about 3 a.m. Monday.

Officials say one adult died at the scene and another died at a hospital. They will not be identified until family members are notified.

Firefighters said the bitterly cold weather and waist-high snow made fighting the fire more difficult. Authorities said a nearby fire hydrant had been cleared of snow.

A heated MTBA bus was brought in for firefighters to use to warm up.

Officials say a firefighter suffered burns.

No other details were immediately available.