Undercover cops stormed a street in Blackley after people reported seeing a man with a firearm.
It turned out it was a BB gun.
The force helicopter was deployed in the search for the apparent gunman after the alarm was raised at around 4pm on Friday.
A Greater Manchester Police spokesman said two people were held following the incident, but not formally arrested.
Witnesses reported seeing a large police presence on Hilldale Avenue, a small residential street just off Rochdale Road.
Alice Williams tweeted: “HUGE Police presence on Hilldale Avenue, in Blackley #manchester. Police chopper, undercover cop cars and SUVs.”
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A GMP spokesman said: “Police were called to Rochdale Road, Blackley, shortly after 4pm to a report of a man in possession of a firearm.
"Officers attended and detained two people. The firearm has been confirmed as a BB gun.
"Enquiries are ongoing."
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