The cause of a deadly house fire on a northern Ontario First Nation has yet to be determined.

The early morning fire broke out last Thursday on the Kitchenuhmaykoosib Inninuwug First Nation, located about 600 kilometres north of Thunder Bay, Ont.

A single mother and four of her children, aged six, seven, nine, and 12, were killed in the blaze.

Crews have yet to officially identify and remove the victims’ remains from the home.

Kitchenuhmaykoosib Inninuwug First Nation Chief Donny Morris said fire marshal officials were still investigating, but the weather was making it difficult.

Morris said the community of roughly 1,000 has been hit hard by the tragedy.