Halifax Regional Police aren't sure if the man arrested after a firearm was found on a city bus today was connected to an earlier report of a man seen with a rifle in the downtown core.

Chief Jean-Michel Blais told CBC News the report of a man with a rifle caused the significant police presence downtown. A man was later arrested after reports of a firearm on a city bus.

Initially, Blais said the reports were not connected, but later clarified police have not determined if the incidents were connected.

Police received a report of one man with a gun near Brunswick Street and Duke Streets in Halifax early Thursday. (Anjuli Patil/CBC)

Police received a call about a white man wearing black cargo pants and an ear piece, concealing what was reported to be a rifle wrapped in black cloth at 8:36 a.m.

At 11 a.m., officers got a call about a man who had left a firearm on a Halifax Transit bus. The man, 25, walked southbound on Albemarle Street and was arrested near Argyle and Carmichael streets.

The firearm was recovered from the bus.

They have not released any information yet on what kind of gun they seized or why they arrested the man they did.

Buildings throughout the downtown area, including Dalhousie University and Citadel High School, were locked down while police responded to the gunman report, but the lockdowns are lifting.

Blais said the city force was on heightened alert, but was otherwise back to "business as usual."

We can confirm that there were no threats made to anyone, no shots fired and no reports that an armed man entered any building. - Halifax Regional Police Const. Pierre Bourdages

"The bad guys and bad girls out there want our lives to be disrupted. They want us to be fearful. The way that we fight back individually and collectively is to not be fearful, to continue with our lives, and to continue to be productive citizens who respect the democratic process," he said.

Const. Pierre Bourdages said both matters remain under investigation.

"We can confirm that there were no threats made to anyone, no shots fired and no reports that an armed man entered any building. Further, we have no information at this time to suggest that the incidents today in Halifax are connected to the tragic incidents in Quebec and Ottawa this week," he said.

"We recognize that today was alarming for everyone in downtown Halifax and those who had loved ones in the area. While we responded to these incidents as we would any weapons complaints, there is undoubtedly increased vigilance on everyone’s part. We thank everyone for abiding by our officers’ directions and for remaining calm in what was an alarming situation for our citizens."

Police are looking for any related information and possible witnesses. People are asked to call at (902) 490-5020.