Alaska authorities say four people have been killed in a house fire near Caswell.

Alaska State Troopers say the home in a rural area about 55 miles north of Anchorage was engulfed in flames when they arrived early Tuesday. A passer-by noticed flames at the home and reported the fire.

Several fire crews from surrounding towns responded to the blaze.

Details were not immediately available.

Troopers, the Alaska Bureau of Investigation and the state fire marshal's office are investigating.