On Fox News earlier Wednesday, Kudlow described an unidentified auto executive's offer to call back workers to idled plants to make the medical devices needed to treat critically ill virus patients, and said it was made "on a voluntary basis for civic and patriotic reasons". The carmakers' North American factories build their most profitable trucks and sport utility vehicles, such as Fiat Chrysler's Jeep Wrangler, GM's Chevrolet Silverado pickup and the Ford F-series truck line.
Ford said its plants will close after Thursday evening shifts, through March 30, while GM's closures will start today and take several days to finish.
GM and FCA could not immediately be reached to comment.
Industry analysts have said it will be hard to keep the factories open for very long as the COVID-19 virus spreads.
Ford closed an assembly plant in MI on Wednesday morning after an employee tested positive and "is thoroughly cleaning and disinfecting the building", the statement said. There were no details on when it would reopen.
Jessica Caldwell of Edmunds.com described the announcement as "a seismic move by the Detroit 3, but also a commendable one". FCA said it would update its financial guidance when it has greater visibility on the epidemic's impact on the market.
Trump said he would invoke another law that would allow US authorities to turn back migrants seeking to cross the southern border of the United States illegally. "By taking a shutdown and working through next steps, we protect UAW members, their families and the community", said Rory Gamble, president of the UAW.
"We have been taking extraordinary precautions around the world to keep our plant environments safe, and recent developments in North America make it clear this is the right thing to do now", GM CEO Mary Barra said in a statement.
GM's Barra, 58, suggested ways the company could help during the crisis, a person familiar with the matter said. GM said pay was still being negotiated with the United Auto Workers union.
Ford announced Tuesday that it was halting production in Europe due to the coronavirus, joining Volkswagen and other leading automakers in suspending work. In California, the automaker has kept its vehicle plant running, albeit with reduced staff numbers, despite a lockdown in the area and the local sheriff department, in this case Alameda County Sheriff, describing Tesla as a non-essential business.