Trump 2nd term live updates: Trump falsely claims Ukraine started war with Russia

All but 28 of the roughly 300 fired National Nuclear Security Administration employees have been rehired, multiple sources told ABC News.

Many of those terminated employees received the news on Tuesday. Last week, the employees were frantically told their firings were put "on pause" as agency leadership decided who should stay and who should go. Most of those who were fired had administrative roles, sources told ABC News.

The Department of Energy did not respond to a request for comment.

-ABC News' Jay O'Brien

In a post on his social media platform Truth Social on Tuesday, President Donald Trump again called for "cleaning house" at the Department of Justice.

"Over the past four years, the Department of Justice has been politicized like never before. Therefore, I have instructed the termination of ALL remaining 'Biden Era' U.S. Attorneys. We must 'clean house' IMMEDIATELY, and restore confidence. America’s Golden Age must have a fair Justice System - THAT BEGINS TODAY!" Trump posted.

-ABC News' Hannah Demissie

The Trump administration is expected to begin layoffs at the Internal Revenue Service as soon as tomorrow, multiple sources told ABC News.

Management was informed on Tuesday to expect probationary employees to be affected and to prepare to collect ID cards and government-issued equipment, sources said.

It is not immediately clear how many probationary employees will be affected. ABC News previously reported that 15,000 IRS employees had been identified as probationary.

-- ABC News' Will Steakin, Olivia Rubin, and Anne Flaherty

When asked whether he was concerned about the thousands of federal employees fired over the weekend as part of his administration’s desire to cut costs, Trump said, “No, not at all,” telling reporters, “We have to just do what we have to do.”

Instead, he focused on the “amazing” findings he claims they have uncovered, emphasizing that this is what he was elected to do.

“In some cases, they'll fire people and then they'll put some people back, not all of them, because a lot of people were let go,” he said in regards to the firing and rehiring of certain employees that occurred over the weekend.