The Ambassador Bridge border crossing was fully reopened late Monday afternoon following a police investigation into an "isolated incident" of possible explosives found in a vehicle.
Police said they detained one person in connection with the probe that significantly hampered traffic across the bridge linking Windsor, Ont., with Detroit, Mich.
The Canada Border Services Agency said normal operations resumed at the bridge just before 5 p.m.
Police in Windsor had initially said that the bridge was closed to all traffic earlier in the day but later clarified that some vehicles had continued to move from Canada to the U.S. during their investigation.
The force said the CBSA had alerted them on Monday morning after possible explosives were found in a vehicle in the secondary inspection area of the bridge complex.
Police said the driver of the vehicle was detained and was in CBSA custody.
"No other persons are believed to be involved in this incident," Windsor police wrote on Twitter. "This is believed to be an isolated incident."
The force also said no direct threats were made to places or people in connection with the possible explosives found.
The CBSA said it worked closely with emergency officials on both sides of the border to monitor the situation and minimize traffic disruptions through the day.
"The Agency thanks travellers and businesses for their patience as the border operations resume," the federal agency said, noting it would not provide additional details.
Vehicles affected by the closure were rerouted to the Windsor-Detroit Tunnel and the Blue Water Bridge in Sarnia, Ont.
The privately owned Ambassador Bridge is critical to trade between Canada and the U.S.
This report by The Canadian Press was first published Oct. 4, 2021.
This story was produced with the financial assistance of the Facebook and Canadian Press News Fellowship.
Noushin Ziafati, The Canadian Press