President-elect Donald Trump's transition team on Tuesday signed an agreement to allow the Justice Department to conduct background checks on his nominees and appointees after a weeks-long delay.

The step lets Trump transition aides and future administration staffers obtain security clearances before Inauguration Day to access classified information about ongoing government programs, an essential step for a smooth transiton of power. It also allows those nominees who are up for Senate confirmation to face the background checks lawmakers want before voting on them.

Teams of investigators have been standing by to process clearances for Trump aides and advisers.

“This agreement with the Department of Justice will ensure President Trump and his team are ready on Day 1 to begin enacting the America First Agenda that an overwhelming majority of our nation supported on Election Day," said Susie Wiles, Trump's designate to be White House chief of staff.

The announcement comes a week after the Trump transition team signed an agreement with the Biden White House to allow transition staff to coordinate with the existing federal workforce before taking office on Jan. 20. The White House agreement was supposed to have been signed by Oct. 1, according to the Presidential Transition Act, and the Biden White House had issued both public and private appeals for Trump's team to sign on.

Security clearances are required to access classified information, including on ongoing operations and threats to the nation, and the Biden White House and outside experts have emphasized to Trump's team the importance of having cleared personnel before Inauguration Day so they could be fully briefed and ready to run the government.

Republican Senators have also insisted on FBI background checks for Trump's nominees before they face confirmation votes, as has been standard practice for decades. Lawmakers have been particularly interested in seeing the findings of reviews into Trump's designated nominee for defense secretary, former Fox News host Pete Hegseth, and for Rep. Tulsi Gabbard to be director of national intelligence.

“That's why it's so important that we have an FBI background check, a committee review of extensive questions and questionnaires, and a public hearing,” said. Sen. Susan Collins, R-Maine on Monday.

John Thune, the incoming Senate Republican leader, said the Trump team “understands there's going to have to be a thorough vetting of all these nominees.”