"This is the implementation of the salaried actions announced late a year ago", GM said in an emailed statement. In addition, GM will also begin to slash its global executive workforce by 25 percent but has not announced a timeframe in which it will begin white collar layoffs.
Pat Morrissey, a GM spokesman, said a "vast majority" of the layoffs - expected to be approximately 4,000 people - will be implemented in the next two weeks on a staff-by-staff, location-by-location basis.
When GM CEO Mary Barra made the announcement, she met with legislators on Capitol Hill about why her company planned to close four American plants. The company calls these firings "involuntary layoffs".
GM is expected to release its fourth-quarter earnings report on Wednesday. GM said the actions - which were roundly criticized by United States and Canadian politicians - would save $6 billion in costs. GM said in November it would end USA and Canadian production of the Chevrolet Cruze, Volt, Impala, the Buick LaCrosse and the Cadillac XTS and CT6 sedans.
In addition, GM will stop building several models now assembled at those plants.
Plants in Baltimore, Maryland, and the suburban Detroit community of Warren, Michigan, which make powertrain components, have no products assigned to them after 2019 and are at risk of closure.
The company said last October that it would offer buyouts to 18,000 workers with more than 12 years with the company across its North American operations as part of cost-cutting efforts.
GM said some 2,250 workers accepted severance agreements by November 19. Since then, the company has cut about 1,500 contract jobs and more than 2,250 workers have taken a voluntary buyout, the report said. But 2,700 USA workers will be offered jobs at other factories.
"You know, the United States saved General Motors, and for her (Barra) to take that company out of OH is not good", Trump said past year.