Police officers armed with guns were sent to London Road to try and arrest a man who allegedly made threats to kill.
The road was shut between the Peacock pub junction and New Road while officers tried to trace the man.
The cordon has now been lifted by officers.
A police spokeswoman said: “Officers were attempting to arrest a man in connection with threats to kill, but have been unable to trace him.
“Firearms officers and the dog unit were deployed as a precautionary measure.”
The spokeswoman said the threats had been made at 2pm - but they were not made in a public place.
The road was re-opened at about 4.40pm.