(NewsNation Now) — Michigan Gov. Gretchen Whitmer urged Canadian authorities to quickly resolve a standoff with protesters over COVID-19 restrictions that culminated in a blockade of a bridge between Canada and Detroit.

“My message is simple: reopen traffic on the bridge,” she said in a statement on social media. “The blockade is having a significant impact on Michigan’s working families who are just trying to do their jobs. Our communities and automotive, manufacturing, and agriculture businesses are feeling the effects. It’s hitting paychecks and production lines. That is unacceptable.”

The bumper-to-bumper demonstration by the self-proclaimed Freedom Truck Convoy entered its fourth day Thursday at the Ambassador Bridge connecting Windsor, Ontario, to Detroit, disrupting the flow of auto parts and other products between the two countries.

Auto-industry groups backed by the city of Windsor are reportedly seeking an injunction to end the blockade. Windsor Mayor Drew Dilkens said in a news briefing Thursday he hopes the injunction will be before a judge later today.

“The individuals on site are trespassing on municipal roads and if need be will be removed to allow for the safe and efficient movement of goods across the border,” he said. 

The bridge carries 25% of all trade between the two countries, and Canadian authorities expressed increasing worry about the economic effects.

On Thursday, General Motors confirmed to NewsNation it has canceled two shifts at one Michigan factory and has been rerouting trucks to keep another plant running amid a parts shortage.

Late Wednesday, Ford said that parts shortages forced it to shut down its engine plant in Windsor and to run an assembly plant in Oakville, Ontario, on a reduced schedule.

“This interruption on the Detroit-Windsor bridge hurts customers, auto workers, suppliers, communities and companies on both sides of the border,” Ford said in a statement. “We hope this situation is resolved quickly because it could have widespread impact on all automakers in the U.S. and Canada.”

The demonstrators in Ottawa say they feel they have nothing to lose.

“Everybody here is struggling. Most of us don’t have work. Most of us hitchhiked,” Kelsey Spencer told NewsNation. “Some of us drove. We’re all here for a better cause, we know Canada is better than this.”

“I think it’s something we have to stick out,” Shannon Veurink, whose husband is a trucker, told NewsNation. “Our family is in complete agreement that no matter what happens, that we’re behind this men, at whatever cost.”

To avoid the blockade and get into Canada, truckers in the Detroit area had to drive 70 miles north to Port Huron, Michigan, and cross the Blue Water Bridge, where there was a 4½-hour delay leaving the U.S.

Prime Minister Justin Trudeau has stood firm against an easing of Canada’s COVID-19 restrictions in the face of mounting pressure by protesters. Trudeau defended the measures the federal government is responsible for, including the one that has angered many truck drivers: a rule requiring truckers entering Canada to be fully vaccinated, which took effect Jan. 15.

About 90% of truckers in Canada are vaccinated, and trucker associations and many big-rig operators have denounced the protests. The U.S. has the same vaccination rule for truckers entering the country, so it would make little difference if Trudeau lifted the restriction.

Protesters have also been blocking the border crossing at Coutts, Alberta, for a week and a half, with about 50 trucks remaining there Wednesday. And more than 400 trucks have paralyzed downtown Ottawa, Canada’s capital, in a protest that began late last month.

In an attempt to dispel any rumors, a spokesperson for the Midwest Truckers Association said in a statement: “There’s no organized effort that we or officials know of that truckers will protest in the U.S.”

According to the spokesperson, truckers are getting paid more than they ever had, and in the short term, the bridge blockade is an inconvenience.

In the long term, the blockade could cause some issues. According to the spokesperson, truckers can move some auto parts, but not whole vehicles if it continues.