BILLINGS, Mont. (AP) — Two Montana inmates were charged with attempted murder Tuesday after allegedly using makeshift weapons to attack corrections officers in a county jail, sending one of the officers to the hospital with stab wounds to the head.

The two inmates pleaded not guilty during court appearances via video from the Yellowstone County jail.

The two officers were targeted in an unprovoked attack Saturday night, Sheriff Mike Linder said. The attack was captured on security cameras but Linder declined to release the footage.

At Tuesday’s hearing, prosecutor Hojae Chung with the Yellowstone County Attorney’s Office said one of the inmates used a makeshift knife to repeatedly stab one of the officers in the back of the head, causing serious bleeding. That officer was treated at a hospital and released later that night and is expected to make a full recovery, the sheriff said.

Judge Bradley Kneeland set bond on Tuesday at $1 million for Myron Scott Goes Ahead, 20, and $500,000 for Ashtin Zant Glen, 18. The two inmates face additional weapons charges. They could be sentenced to up to life in prison if convicted on attempted murder

Goes Ahead was being held in jail while awaiting trial on two murder charges stemming from a shooting last year in Billings that killed a man, who then fell on a boy who also died. Goes Ahead and another person were accused of stealing ammunition from a sporting goods store and then firing a spray of bullets into the house with the victims. The boy, who was almost 1 year old, suffocated after the man who had been carrying him was shot and fell on top of him, authorities said.

Glen was being held on charges including attempted murder. Authorities said he’s accused of shooting and wounding a man during a gunfight last year and later firing at deputies as he fled from the scene.