Several automakers have cut production as the protest blocking the Ambassador Bridge continues to disrupt supply chains and bring cross-border traffic to a halt.

Operations on both sides of the border have been affected by the protest, which began on Monday, blocking traffic between Detroit, Mich. and Windsor, Ont. Police have been redirecting commercial vehicles to the Blue Water Bridge in Sarnia. Ont, and have urged people to avoid the area and use alternate routes.

Toyota Motor Corp. (TM) says its three Ontario plants have been idled as the company grapples with supply shortages. A spokesperson for the automaker says disruptions are expected to continue through the weekend, and production plans will be adjusted accordingly.

General Motors (GM) also cancelled shifts at its factory outside of Lansing, Mich. The company did not say if operations in Canada have been affected by the protest.

Ford (F) says it is operating its production facilities in Oakville and Windsor at a reduced capacity as a result of the Ambassador Bridge blockade.

"This interruption on the Detroit-Windsor bridge hurts customers, auto workers, suppliers, communities and companies on both sides of the border that are already two years into parts shortages resulting from the global semiconductor issue, COVID and more," the company said in an emailed statement.

"We hope this situation is resolved quickly because it could have widespread impact on all automakers in the U.S. and Canada."

Stellantis says its North American plants are running as of Thursday morning after production was scaled back on Wednesday "due to parts shortages caused by the closure of the Detroit-Windsor bridge."

The Ambassador Bridge is the busiest border crossing between Canada and the U.S., with an average of 40,000 commuters, tourists and truck drivers crossing the border carrying more than $300 million worth of goods each day.

The border crossing is an especially critical link for the North American automotive industry. Flavio Volpe, the president of the Automotive Parts Manufacturers' Association (APMA), says about $100 million in automotive parts cross the Ambassador Bridge on a daily basis. Given most automotive manufacturers operate under a just-in-time production model, Volpe says there are only enough parts "for a day or two" before production will be affected.

Linda Hasenfratz, the chief executive of Canada's second-largest auto parts manufacturer Linamar (LNR.TO), says in a statement that the company is watching the situation at the border "with concern" and urged the protesters to leave.