A day after the Trump administration ended its deferred resignation offer to the nation’s two million federal government employees, the administration on Thursday began mass layoffs across multiple federal agencies in a move that is expected to impact thousands of employees, sources familiar with the matter told ABC News.

The layoffs, part of Trump’s campaign pledge to slash the federal government, initially impacted probationary employees — recent hires who joined the federal workforce within the last one to two years, depending on the agency, and have fewer protections.

Among the agencies experiencing layoffs were the Department of Education, the Consumer Financial Protection Bureau, the Office of Personnel Management, the Environmental Protective Agency, the General Services Administration and the Small Business Administration.

Some additional agencies were also directed to begin their layoffs Thursday, sources said.

At some agencies, workers received written notice via email that they had been let go.

At OPM, workers joined a call with a prerecorded message from the acting director notifying them of their firing, according to someone familiar with the call. About 200 probationary workers were on the call, sources said.

Prior to the layoffs, agencies had been directed by the Office of Personnel Management to compile lists of probationary employees at their agencies, sources familiar with the matter told ABC News.

Officials told ABC News that more than 73,000 federal accepted the administration’s buyout offer, which offered full pay and benefits until September for any federal employee who accepted the deferred resignation.