Fewer officials are allowed to listen in on President Trump’s phone calls with foreign leaders, according to a new report, after the political bomb the President detonated during his infamous July call with Ukrainian President Volodymyr Zelensky.

Multiple White House sources told CNN in a Friday report that Trump’s senior aides have further limited the number of administration officials who listen to the President’s phone calls with foreign leaders and that the memos of the calls are being distributed to a far smaller group within the White House.

The sources also told CNN that the effort to restrict access to the calls is an attempt to prevent the conversations from becoming public.

“Nobody is allowed on the calls,” a White House official told CNN.

CNN noted that in past presidencies as well as earlier in the Trump administration, a larger pool of officials could listen in on the President’s phone calls with foreign leaders, which included aides with expertise on the countries being phoned or an issue being discussed.

Nowadays, multiple White House officials told CNN that Trump is joined by just a handful of aides who are signed approved by National Security Adviser Robert O’Brien — who often joins the call along with his deputy Matt Pottinger, Secretary of State Mike Pompeo, acting chief of staff Mick Mulvaney and his deputy Rob Blair, and Vice President Mike Pence’s national security adviser Lt. Gen. Keith Kellogg.

The new effort has a sneering nickname, too, according to CNN: “The Vindman Rule.” It refers to Lt. Col. Alexander Vindman, who listened in on Trump’s call with the Ukrainian president and raised alarm over the conversation. Vindman testified before the House Intelligence Committee during the impeachment inquiry.

It’s not the first time Trump’s aides have made efforts to tamp down who has access to the calls. In 2017, the then-National Security Adviser Gen. H.R. McMaster made efforts to restrict who could listen in on Trump’s calls after transcripts of the President’s discussions with the leaders of Australia and Mexico leaked. However, some of those restrictions were lifted when John Bolton took over the role.

Read CNN’s report here.