Police say it was an 'isolated incident' which they dealt with at Tesco in Ramsey, with two suspects now in custody.
The store on Bowring Road was closed and the area cordoned off earlier this afternoon, Saturday, February 7.
Footage filmed by the public shows armed officers arresting a suspect on a public bus.
Officers went on to say the supermarket and its car park will stay closed at this time, 4.20pm.
Further updates will be released via the police's Facebook page.
Manx movie star featuring at Cannes
Registrations open for popular charity obstacle course
Northern roads to close for cycling
Hundreds of job offers withdrawn over vetting failures
New cafe for the capital
Crash causes disruption at Quarterbridge
Stamps mark Manx connection to US War of Independence
Swiss ambassador visits Island