Police closed a busy Brighton junction after reports of a man armed with a gun in a flat.
Officers shut Preston Circus in Brighton to traffic at about 9pm this evening before an apparent armed siege.
Sussex Police said it was called at about 7.30pm and officers closed the roads in the London Road area while a 30-year-old man was detained.
A police spokesman confirmed the man has been arrested for firearms offences and remains in custody this evening.
He added: "No one was injured in the incident and Sussex Police would like to thank people for their patience while the roads were closed."
Earlier, witnesses said there was an armed siege ongoing, apparently focused on the property above a Caribbean takeaway.
A spokesman for Sussex Police told The Argus just before 10pm there was an incident ongoing.
However he refused to confirm any details adding it would only release information through a media officer.
A passer-by said officers were seen leaving a property at about 10.20pm and by 10.30pm all police vehicles had left the scene.
Brighton and Hove Bus Company confirmed London Road had been shut in both directions between Baker Street and Preston Circus at about 9pm.
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