Two men are in custody after after armed police were deployed to reports of a man with a firearm at 9.40am on Clarendon Road, Hove.
The suspects, a 28-year-old man from Worthing and a 41-year-old man from Brighton were both arrested on suspicion of possessing a firearm without a certificate and remain in police custody.
A Sussex police spokesman said: “This is believed to be an isolated incident that does not pose a wider risk to the community.”
The road was shut for several hours with a police cordon in place.