Parts of a national forest near Anaconda, Montana, were closed late Saturday as authorities expanded their search for the gunman accused of killing four people at a bar on Friday morning.

Deputies spent Saturday traversing a rugged mountainous area of Montana with helicopters overhead as a manhunt for a military veteran suspected of fatally shooting four people at a bar stretched into a second day with no capture.

Authorities urged residents to stay inside and on high alert because they consider Michael Paul Brown armed and dangerous.