Four teenage boys face arson charges in connection with a large fire at a child and family services building in Norway House in northern Manitoba.

The blaze started shortly before 8:30 a.m. CT Thursday at the Kinosao Sipi Minisowin Agency Building, which housed the offices of a child and family services agency.

No one was inside the building at the time of the fire. The structure was undergoing an expansion.

The boys, who are 15 and 16 years old, are also being charged with mischief and with breaking into two separate business locations, RCMP said in a release late Friday.

Two of the accused are from Norway House, one 16-year-old boy is from Winnipeg, and another 16-year-old is from Cross Lake, Man., according to police.

All four are in custody and are scheduled to appear in youth court in Thompson, Man., on Monday.