The Justice Department's ability to conduct surveillance activities has been significantly rolled back, with new restrictions coming after accusations the Obama administration and FBI spied on President Donald Trump in 2016, Attorney General William Barr said Tuesday in a memo.

The alleged surveillance of Trump's 2016 campaign was done as part of FBI’s investigation into potential coordination with Russia. Trump has in the past called this investigation a “witch hunt,” a common phrase he has used to brand any force acting against him.

“What happened to the Trump presidential campaign and his subsequent administration after the president was duly elected by the American people must never happen again,” read one of the two memos detailing the changes.

The restrictions give special focus to “elected officials, candidates for federal office or their staff and advisers” that may be targeted for surveillance. This includes attempts to set up wiretaps, conduct physical searches, and use administrative subpoenas. One of the major new requirements says that the FBI must consider “defensive” briefing for potential targets that will inform them of the action taken against them.

Applications for surveillance must then also get approval from the Attorney General and FBI director, before being sent to a FISA court for further approval.

“When those activities involve federal elected officials, federal political candidates, or their respective staff members, the Department must be especially vigilant,” one of the memos explained. “Such intelligence activities must be subject to rigorous review to ensure that they are justified and nonpartisan, are based on full and complete information, take into account the significant First Amendment interests at stake, and do not undermine the political process.”