Ford and Toyota have both said they were halting some North America production as anti-coronavirus mandate protesters blocked US-Canada border crossings which have prompted warnings from governments both sides of the border of economic damage.

A Reuters report on Nikkei Asia said horn-blaring protests had being causing gridlock in Canadian capital Ottawa since late January and, from last Monday night, truckers shut inbound Canada traffic at the Ambassador Bridge, a supply route (from the city across to Windsor) for Detroit’s car makers.

The report said several carmakers had now been affected by the disruption near Detroit but there were other factors such as severe weather and a shortage of semiconductor chips.

Toyota told the news agency it did not expect to produce vehicles at its Ontario factories for the rest of the week, output has been halted at a Ford engine plant and Stellantis assembly has also been disrupted.

Starting as a “freedom convoy” occupying downtown Ottawa opposing a vaccinate-or-quarantine mandate for cross border truckers mirrored by the US government, protesters have also aired grievances about a carbon tax and other legislation.

“I think it’s important for everyone in Canada and the United States to understand what the impact of this blockage is – potential impact – on workers, on the supply chain, and that is where we’re most focused,” White House spokesperson Jen Psaki was quoted as saying on Wednesday.

The US government was working with Canadian authorities to reroute traffic to the Blue Water Bridge, which links Port Huron in Michigan with Sarnia in Ontario, amid worries protests could turn violent, Psaki told Reuters.

Bank of Canada governor Tiff Macklem had called for a swift resolution, according to the report.

“If there were to be prolonged blockages at key entry points into Canada that could start to have a measurable impact on economic activity,” he said. “We’ve already got a strained global supply chain. We don’t need this.”

The protests were disrupting jobs too and “must end before further damage occurs,” Canadian emergency preparedness minister, Bill Blair, told Reuters.

The report said Ford suspended engine output in Windsor while its Oakville vehicle assembly plant near Toronto was operating with a reduced schedule, as it warned the Ambassador Bridge closure “could have widespread impact on all automakers in the US and Canada”.

Stellantis also faced a shortage of parts at its assembly plant, also in Windsor, where it had to end shifts early on Tuesday, but was able to resume production on Wednesday.

Protesters have said they were peaceful, but some Ottawa residents claimed they were attacked and harassed, Reuters added (a local told just-auto on Wednesday there had been traffic hold-ups in her suburban neighbourhood). In Toronto, streets were being blocked, Reuters added.

The report said downtown Ottawa residents had criticised police for their initially permissive attitude toward the blockade but authorities began trying to take back control last Sunday night with the seizure of thousands of litres of fuel and the removal of an oil tanker truck.

Police have asked for reinforcements – both officers and people with legal expertise in insurance and licensing – suggesting intentions to pursue enforcement through commercial vehicle licences, the news agency noted, adding, as the authorities attempt to quell demonstrations in one area, they pop up elsewhere.

“Even as we have made some headway in Ottawa, we’ve seen an illegal blockade emerge in Windsor,” public safety minister Marco Mendicino told Reuters.