The public has been warned to stay away from a retail park in the Midlands as police deal with an "ongoing incident".
Footage posted on social media appeared to show armed officers at the scene in Bermuda Park in Nuneaton.
Warwickshire police tweeted: "Officers are currently dealing with an ongoing incident at Bermuda Park, #Nuneaton. Please avoid the area."
A staff member in the retail park, which includes a cinema, restaurants, Holiday Inn and fitness centre, said: "We are on lockdown."
Unconfirmed reports on social media said armed officers were dealing with a man who had taken hostages inside the bowling alley there.
A witness told BBC News: "When we were leaving there were police standing around the bowling alley, there were police cars outside the main entrance, with police officers in full body armour."
Witness Sarah Fleming said a police officer confirmed to her that an armed man was holding hostages at MFA Bowl.
She told Sky News: "We got notification that someone had a shotgun inside the bowling alley. We were inside Frankie and Benny's and obviously we went on lockdown, no-one was allowed in or out. Then we had notification from the police that he actually had hostages.
"Everyone has been a bit up in the air, don't know what's going on and obviously there is a lot of children in here as well which has been quite an experience for them. So everyone is a little bit scared at the minute."
The restaurant was put on lockdown after a manager went to the nearby cinema, where staff confirmed the situation, she added.