Hamilton police deployed its armoured rescue vehicle and tactical team after a call that said someone was being shot and that officers were going to be shot.
Police closed off Wellington Street North and after securing the area, entered a home but found no firearm or "person of interest."
At the scene, Inspector Glenn Bullock said the information that led to the road closures, tactical vehicle deployment and ambulance at the corner of Cathcart and Robert Streets, "looks to be false."
Police mobilized shortly after 3:20 p.m. "after receiving a call from an agitated male advising that he had shot someone in the home. The male advised that he was in possession of a loaded firearm and would shoot police if they approached," police said in a release.
Wellington Street was closed between Barton and Cannon for the investigation, but was reopened shortly before 5 p.m.
Police had asked residents to stay clear of the area and allow first responders to do their jobs.
Police also asked residents not to post pictures of police's response for the safety of the officers and the public, until it was deemed safe.