Warwickshire police in central England said on Twitter: "Officers are dealing with ongoing incident at Bermuda Park, Nuneaton and confirm this incident is unconnected to any terrorist activity", but gave no further details.
Mehdi Afshar, chief executive of MFA Bowl which owns the alley, told Sky News that a man had taken two members of staff hostage at the complex, which includes a cinema, a gym and several restaurants.
Pictures on Twitter showed armed police at the complex and local media reported that roads leading to it had been closed off. Some people were being allowed to leave the complex, another witness told Sky News.
The West Midlands Ambulance Service said on Twitter: "We have a number of resources at the scene ... The air ambulance has now left. There are no casualties at present."
(Reporting by Elizabeth Piper, editing by David Evans)
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)