USDA says SNAP benefits won't be issued on Nov. 1

President Donald Trump confirmed mass firings of federal workers began Friday amid the government shutdown and said the layoffs would be "Democrat-oriented."

Earlier, White House Office of Management and Budget Director Russ Vought said in a social media post "The RIFs have begun," referring to reductions-in-force.

Speaking to reporters from the Oval Office on Friday, Trump did not specify which agencies were laying off workers or the exact number of layoffs but said it would be "a lot."

Trump continued to lay blame for the shutdown on Democrats in Congress.

"They started this thing so it [layoffs] should be Democrat-oriented," Trump said.

Republican Sen. Susan Collins, the chair of the Senate Committee on Appropriations, sharply criticized OMB Director Russ Vought's decision to fire federal workers in a new statement released on Friday.

"I strongly oppose OMB Director Russ Vought's attempt to permanently lay off federal workers who have been furloughed due to a completely unnecessary government shutdown caused by Senator Schumer. Regardless of whether federal employees have been working without pay or have been furloughed, their work is incredibly important to serving the public," she said.

"Arbitrary layoffs result in a lack of sufficient personnel needed to conduct the mission of the agency and to deliver essential programs, and cause harm to families in Maine and throughout our country," she added.

-ABC News' Ben Siegel and Mariam Khan

The American Federation of Government Employees, which represents over 800,000 federal employees, blasted the Trump administration over its federal firings, calling them "disgraceful" and "illegal."

"Federal workers are tired of being used as pawns for the political and personal gains of the elected and un-elected leaders. It's time for Congress to do their jobs and negotiate an end to this shutdown immediately," AFGE National President Everett Kelley said in a statement.

"In AFGE's 93 years of existence under several presidential administrations – including during Trump's first term – no president has ever decided to fire thousands of furloughed workers during a government shutdown," he added.

The AFGE filed a lawsuit against the Office of Management and Budget last month over mass firings.

Senate Majority Leader John Thune said the White House is "going to have to do some things" to pay troops amid the ongoing government shutdown but did not specify details.

"I suspect that they're probably going to be, yeah, pretty soon they're going to have to do some things. I think to their credit, the White House has, now for 10 days, laid off doing anything in hopes that enough Senate Democrats would come to their senses and do the right thing and fund the government," Thune said when asked if President Trump should move money around to pay troops.

Thune signaled he was not open to getting rid of the filibuster to allow the Republicans' funding bill to pass with a simple majority, rather than the current required 60 votes, saying it's "something that makes the Senate the Senate."

-ABC News' Fritz Farrow