The Ambassador Bridge connecting Ontario and Detroit, Mich., has reopened fully after being partially closed for several hours Monday afternoon as police checked the area for "possible explosives," Windsor police said.
At about 7 p.m. ET, Windsor police tweeted that officers were no longer at the scene. The tweet also said more updates will be provided Tuesday.
At 2:32 ET, police tweeted the "driver of the involved vehicle" was being detained pending further investigation.
The CBSA alerted Windsor Police Service (WPS) after the possible explosives were found inside a vehicle in the secondary inspection area at the border crossing.
"No threat was associated to this [and] this is believed to be an isolated incident," police said on Twitter just after noon ET.
Earlier Monday, the WPS said officers, including the explosive disposal unit, were on scene and the area was evacuated.
Traffic was rerouted to the Windsor-Detroit Tunnel and Bluewater Bridge near Sarnia, Ont.
"Local CBSA management is working closely with emergency officials on both sides of the border monitoring the situation and acting to minimize traffic disruptions," CBSA said in a statement to CBC News.
As of early afternoon, the international crossing remained closed to incoming travellers, but open to U.S.-bound traffic. The crossing was fully opened both ways later in the afternoon.
Windsor's ports of entry, which include the bridge and the tunnel, make up the busiest land border crossing in Canada.
A bomb threat in 2012 caused a five-hour closure of the bridge that halted cross-border trucking.
Joe Abramuk, dispatch supervisor for OnFreight Logistics, said the closure was slowing things down for truckers as they were "waiting for something to clear up so we can start bringing the product over,".
The company has 15 to 30 trucks using the border crossing daily. Shutdowns affect "everything from the bottom line to drivers' hours," he said.