A fire tore through an apartment building in Lowell Massachusetts early Thursday morning killing seven, the Associated Press reported. 

The blaze was first reported by a local police officer on a routine patrol just before 4am. It quickly spread, engulfing the entire the three-story, 48-tenant building in flames, leaving the roof burned away, the walls charred and the siding melting.

"Some people jumped from windows, and firefighters rescued others with a ladder," Lowell Fire Chief Edward Pitta said, describing the scene to reporters on Thursday. 

The cause of the fire remains unknown, but all of the dead were located on the third floor of the building while an unspecified number of others taken to a local hospital. 

The names and ages of the victims have not been released and the Red Cross said they are assisting some 55 now homeless survivors.

"It's a tragic day for the city of Lowell," Mayor Rodney Elliott said.