Armed police officers swooped on an address in Gorleston following reports a man had verbally threatened to harm people.
The alarm was raised by a third party at 3.42pm yesterday when officers were called to an address in Gorleston High Street at Icehouse Hill.
However they were unable to trace the man, aged in his 30s.
A spokesman said: 'Enquiries are ongoing to locate him at this time.
'This is being treated as an isolated incident and it is not believed there is any wider threat to the public.'
People at the scene described a heavy police presence with some six or seven police cars including officers with dogs.
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