A tractor trailer drives across the Ambassador Bridge border crossing from Windsor, Ontario in Canada to Detroit, Michigan in the United States on February 14, 2022.

Several car factories that saw operations disrupted last week after protests in Canada blocked a key border crossing with the United States resumed activities on Monday, but some issues lingered.

Trucker-led demonstrations against Canada's Covid-19 restrictions disrupted traffic on the Ambassador Bridge for seven days, but authorities on Sunday cleared out the protestors.

The bridge, which connects Windsor, Canada with Detroit on the American side, is a key route for automakers to ship parts and vehicles back and forth across the border during the .

General Motors, which had to cut shifts at some plants last week amid a shortage of materials, said work resumed as normal on Monday.

"No issues to report," a company spokesperson told AFP.

Stellantis, which also shortened several shifts in Canadian and US plants due to the bridge closure, resumed normal operations, a spokesperson said.

The company did not provide an estimate of projected losses due to the disruptions but said it "will look to make up that production in the coming months."

"We are working with our carriers to get parts into the plants as quickly as possible to mitigate any further disruptions," the spokesperson said.

Toyota, which likewise felt the impact last week at its Canadian factories as well as three sites in the US states of Kentucky, West Virginia and Alabama, said operations have not yet returned to normal.

"All three lines at our plants in Canada are not running still and only certain lines are running at our other three US impacted ," a spokesperson said.

"We're expecting it to improve each day this week as we get all routes back to normal."

Honda said operations on the US side of the border were running.

The company on Friday temporarily suspended one at its Alliston plant on the Canadian side, and on Monday had only one line working, although that was "due to previously scheduled downtime unrelated to the issue."