White House says some employees were fired by mistake

As his administration begins negotiations to end the conflict, which began in February 2022 with Russia's full-scale invasion of Ukraine, President Donald Trump was asked by a reporter who he blamed for the war.

"I think that there were a lot of people to blame," Trump said. "All I can say is, very simply, if I were president, that war would never have happened."

Trump on Thursday suggested Ukraine's NATO aspirations were a factor in Russia's decision to invade.

President Donald Trump on Friday signed an executive order that will strip schools of federal aid if they mandate COVID vaccines -- a largely symbolic move considering that no states currently require them.

The order applies to students and not to teachers or staff. In a fact sheet provided to reporters, the White House said the order was necessary because COVID vaccine mandates were "threatening educational opportunities for students."

Trump's directive also calls on newly-confirmed Health Secretary Robert F. Kennedy Jr. and the incoming education secretary to "provide a plan to end coercive COVID-19 vaccine mandates" and report back on the compliance of schools.

-ABC News' Anne Flaherty and Kelsey Walsh

U.S. District Court Judge Tanya Chutkan has scheduled a 4 p.m. initial hearing on Elon Musk's authority to run the Department of Government Efficiency.

Fourteen states are challenging Musk's role overseeing DOGE and accusing him of being a "designated agent of chaos" whose "sweeping authority" is in violation of the U.S. Constitution. Musk has defended his position by describing his role as the country's "volunteer tech support guy."

Read more about the lawsuit here.

-ABC News' Katherine Faulders

The Department of Energy has paused the firings of hundreds of employees who work for a key agency maintaining the U.S. nuclear weapons stockpile, multiple sources tell ABC News.

Managers with the National Nuclear Security Administration (NNSA) are frantically calling employees back and telling them that -- as of right now -- they're not fired, despite some receiving termination emails and phone calls on Thursday. Their badges are getting turned back on and access to federal systems is being restored, at least temporarily.

Hundreds of probationary employees were terminated Thursday night in the mass Trump administration layoffs. The move prompted concerns of a national security risk because the agency is responsible for maintaining U.S. nuclear weapons, transporting them, and nuclear counterterrorism, among other missions.

NNSA held an all-staff meeting Friday morning, announcing the DOE had agreed to pause the layoffs, due to the agency's national security mission.

NNSA staff tell ABC News they are in a holding pattern. They're still bracing for firings, but possibly not as widespread.

-ABC News' Jay O'Brien