An early Monday morning fire destroyed a synagogue in northern Minnesota.

The cause of the fire at the Adas Israel congregation, a traditional synagogue in Duluth, was unclear, according to local news reports. It appears to have destroyed much of the building.

Firefighters responded to the fire at the Adas Israel Congregation about 2 a.m. Monday and finally knocked it down about four hours later. At daylight, spectators could see the charred remains of the synagogue with some structural walls still standing. Duluth Assistant Fire Chief Brent Consie said the building “is pretty much a total loss.”

There was no immediate word from fire officials on what started the blaze.

The synagogue has 75 members and daily prayer services, according to the St. Paul Jewish Federation.