Detroit's big three carmakers will close their us plants to stop the spread of novel coronavirus under pressure from unions representing about 150,000 hourly workers, British media said.

Ford motor co., general motors Co. and fiat Chrysler LLC confirmed their decisions to close U.S. plants as well as plants in Canada and Mexico.

Shares of the Detroit automakers plunged Monday, with gm closing down 17.3%, ford motor down 10.2% and fiat Chrysler down 9.2%, the report said. The three carmakers' north American plants are responsible for producing the most profitable trucks and sport-utility vehicles.

The decision came less than a day after the big three carmakers and the united auto workers union agreed to keep factories running and free up more time for cleaning by cutting shifts and staff Numbers.

But by the morning of the 18th, the agreement was on hold. Honda motor Co. said it would close its north American plants for six days because of a sharp drop in demand. Meanwhile, a worker at a ford assembly plant in Michigan tested positive for a novel coronavirus.

Ford closed its final assembly building in Wayne, mich., on Monday morning, the report said. The ford motor company said it would close all its north American plants until March 30 for a thorough cleaning after the night shift ends Thursday. Gm's timetable is the same, while fiat Chrysler's is until the end of march.

Nissan motor Co. said it will stop production at its U.S. plants on March 20, April 6. Nissan said there were no confirmed cases of novel coronavirus at any of its plants.

South Korea's hyundai motor Co. closed its assembly plant in Montgomery, Alabama, Thursday morning after an employee tested positive for a novel coronavirus. No details have been released about when hyundai will restart. Toyota motor corp. says it will close its north American plants for two days next week.

The report noted that Detroit's big three automakers have not issued profit warnings, but Germany's BMW said Wednesday that its 2020 profit will be "significantly lower" than last year.

According to the center for automotive research in Ann arbor, mich., the pain may be felt by the U.S. government, which could lose $2 billion in tax revenue if the nation's auto industry is shut down for a week.

Rory gamble, President of the united auto workers union, which has called on Detroit automakers to close their U.S. plants, said in a statement Monday that the closures were "prudent."

"Recent events in North America show that this is the right thing to do," gm CEO Mary barra said in a separate statement.

The union says workers affected by the shutdown are eligible for unemployment benefits and subsidized wages from automakers.