The incident took place in Bridgeport on Wednesday, Dec. 28 at St. Vincent's Medical Center on Main Street.
A man made a threat while being escorted out of the hospital that he was going to "shoot it up," said Scott Appleby, director of Emergency Management.
Appleby said the hospital was put on lockdown as a precaution.
The unidentified man was arrested a short time later by Fairfield Police.
This is a developing story. Check back to Daily Voice for updates.
Click here to follow Daily Voice Windham-Willimantic and receive free news updates.