The Lebanon Police Department is asking people to avoid the area while roads around the hospital have been closed.
Police from Lebanon, New Hampshire, as well as state troopers were on site, the spokesman said. The hospital was under lockdown and it wasn't clear if that was lifted.
"We are assessing the situation now, and will have more information as soon as it becomes available", the hospital said in a statement posted on Twitter.
The city's official website posted that a person was in custody who was believed to be involved in the shooting reports.
Pittsburgh Steelers defeat Cleveland Browns, 21-18, in 2017 regular-season opener
Ben Roethlisberger found tight end Jesse James in the end zone to put the Steelers ahead 14-7 with 45 seconds left in the half. The second Roethlisberger-to-James touchdown combination of the day gave the Steelers a 21-10 lead over the Browns.
TV reports claimed that all workers received an email from the hospital about a "code silver", telling them to get out if possible or otherwise stay put.
Dartmouth-Hitchcock Medical Center is New Hampshire's largest hospital, and is located in the west-central portion of the state.
Mike Barwell, media relations manager, told NH1 News police were on their way to the hospital around 1:45 p.m. Tuesday.
Police flooded the scene and reports of a suspect in custody started coming in about an hour after the first reports of the incident.
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