The Canada Border Services Agency has seized 45 firearms at border crossings in its Southern Ontario Region so far this year.
Ten of those weapons were seized at crossings in Sarnia and Windsor.
On May 15, an Ontario man arrived at the Windsor-Detroit Tunnel and was referred for secondary examination. A sniffer dog helped officers find four prohibited handguns and two high-capacity magazines in a passenger car.
All told, 31 handguns and more than twenty high-capacity magazines have been seized from six crossings.