The Trump administration has begun enforcing new rules that severely limit the number of journalists given press passes that afford them easier access to the White House, according to reporters at The Washington Post.

Dana Milbank, a columnist at the Post who has held a White House press pass for 21 years, wrote Wednesday that his had been revoked as part of a “mass purge” among the greater press corps.

“Trump’s elimination of briefings and other changes have devalued White House coverage anyway. But there’s something wrong with a president having the power to decide which journalists can cover him,” Milbank wrote. “Now, virtually the entire White House press corps is credentialed under ‘exceptions,’ which means, in a sense, that they all serve at the pleasure of press secretary Sarah Sanders because they all fail to meet credentialing requirements.”

The new policy primarily affects reporters who held “hard” passes ― long-term media credentials that allow the quickest access to the White House grounds. Sanders said in March that she would begin to review reporters’ eligibility for the passes, noting that to qualify journalists would need to be “physically present at the White House for your job 90 or more days in a 180-day window of time.”

The rule effectively requires journalists to work from the White House every other day but does not have considerations for trips, weekends or vacations, according to Politico. “Senior journalists” can apply for an exemption (Milbank noted that seven other Post reporters who did not meet the time requirement were granted one, but he was not), and others in the media can apply for shorter-term passes that would have to be re-upped regularly. Sanders is also allowed to grant hard passes for “special circumstances.”

It’s the first time the policy has gone into effect, and Sanders defended the move, saying it came from the Secret Service, who worried about the number of hard passes in existence. “No one’s access is being limited,” she told the Post later Wednesday.

Many journalists took to Twitter to lambaste the move, noting that it was yet another step by the White House to undermine the press corps. Sanders has held only two formal news briefings this year, an abnormally low number compared with previous administrations.