DETROIT – General Motors and Ford Motor Co. said they would close all of their manufacturing sites in the United States, Canada and Mexico until at least March 30 – marking a costly and dramatic step to battle the coronavirus pandemic that the automakers had hoped to avoid.

Fiat Chrysler Automobiles also said it would begin easing production today, through the end of the month.

Ford said the shutdowns will begin after Thursday's shifts. GM said it will begin cutting production Wednesday in a cadence.

“We’re continuing to work closely with union leaders, especially the United Auto Workers, to find ways to help keep our work force healthy and safe – even as we look at solutions for continuing to provide the vehicles customers really want and need,” Kumar Galhotra, Ford’s president of North America, said in a statement . “In these unprecedented times, we’re exploring unique and creative solutions to support our work force, customers, dealers, suppliers and communities.”

As of Tuesday night, the automakers had planned to continue running their plants without a wholesale interruption. In a meeting with UAW leaders, executives agreed to a number of enhanced safety measures, including rotating partial shutdowns and extra time between shifts to allow for extra cleaning.

But on Wednesday, Ford had to close off part of its Ranger plant because a worker there tested positive. Ford’s Explorer plant in Chicago also was down Wednesday because a Lear seating plant that supplies it closed after a worker got the virus.

A six-day manufacturing stoppage across North America announced by American Honda , whose factory workers are nonunion, also helped the UAW pressure the Detroit 3 into a temporary shutdown.Toyota later announced a two-day production halt in North America next week.

"We have agreed to a systematic, orderly suspension of production to aid in fighting COVID-19/coronavirus,” GM CEO Mary Barra said in the company's statement. “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."

FCA halt

FCA said its production suspension will “start progressively today” and last “through the end of March.” Two COVID-19 cases were detected among FCA’s plant workers, one who is employed at the Sterling Heights Assembly Plant and another who works at the transmission plant In Kokomo, Ind.

“While production is paused, the company will put actions into place to facilitate the steps agreed to through the joint task-force set up between the UAW and the automakers,” FCA said in a statement. “Through this period, which we will re-evaluate at the end of this month, FCA will work to enhance its manufacturing operations to facilitate the changes agreed with the UAW including shift timings, structures and enhanced cleaning protocols.”

FCA CEO Mike Manley said “working with the UAW, and having visited many of our plants yesterday, we need to ensure employees feel safe at work and that we are taking every step possible to protect them.”

Manley said FCA will “continue to do what is right for our people through this period of uncertainty.”