LEWISTON — Central Maine Medical Center was locked down for several hours Tuesday after it received a call that someone was going to the hospital with a gun.

The hospital received the call at about 9:15 a.m. through its switchboard. Lewiston police said the caller provided information about someone else issuing “a vague threat of self-harm or potential harm” to others.

The hospital was locked down at 9:30 a.m. because officials could not immediately rule out whether the threat was credible or not, according to hospital spokeswoman Jackie Weder,

CMMC spent most of the day accepting only emergency patients. Visitors were prohibited and patient appointments were canceled. Only time-sensitive procedures went on as planned.

Patients who were ready to be discharged were allowed to leave the building, but employees were encouraged to stay on campus until the end of their shift.

The lockdown was lifted at 4:30 p.m., after CMMC and police concluded the threat was not credible. Visitors were allowed in the building. All other hospital services are expected to return to normal on Wednesday.