EAST MEADOW - A lockdown has been lifted at Nassau University Medical Center after an attack on a corrections officer Wednesday morning.

Union officials tell News 12 a corrections officer guarding an inmate in a hospital room on the ninth floor was attacked from behind by a man with a knife. Police say the officer was slashed behind his ear. There is no word on what sparked the incident.

NUMC says 80 Nassau police officers and corrections officers conducted a floor-by-floor search for the attacker. Police believe the attacker fled the building.

According to hospital officials, the officer was treated with stitches and released.

Police say they are currently interviewing witnesses and reviewing surveillance footage for clues on the suspect’s identity.

Meanwhile, corrections union officials say they are angered by the county's refusal to assign more than one corrections guard to inmates under treatment at NUMC.

The hospital's incoming executive director says security at NUMC is normal for any hospital.

The hospital currently does not have any metal detectors.