PORTLAND — The State Fire Marshal is investigating a fire that killed a 43-year-old man in Portland this morning.

Firefighters were called to 65 Grant St. at 8 a.m. for a report of a fire. The blaze was extinguished quickly and the man was taken to Maine Medical Center where he was pronounced dead as a result of his injuries, police said.

The fire did little damage to the structure beyond the interior of the apartment, police said.

The state Fire Marshal’s Office is working to determine what caused the fire. Police said they have a tentative identity of the man killed but are waiting for confirmation before releasing it.