SALMON Idaho (Reuters) - Police shot and killed a woman brandishing a knife outside a regional medical center in northern Idaho that had been locked down amid reports of a weapons threat, authorities said Wednesday.

Officers investigating the threat late on Tuesday at Bonner General Hospital in Sandpoint said they found a knife-wielding woman who ignored their demands to drop the weapon.

An altercation ensued and officers opened fire and killed the 35-year-old woman, Gary Johnston, detective sergeant with the Bonner County Sheriff’s Office, said in a statement.

"A preliminary investigation indicates the female aggressed the officers while refusing to comply with commands to drop the knife. The officers responded to the threat using lethal force," Johnston said.

Authorities declined to release further details, including the number of officers involved, pending an investigation by the sheriff's office and other law enforcement agencies in Idaho.

(Reporting by Laura Zuckerman; Editing by Daniel Wallis and Eric Walsh)