White House press secretary Sean Spicer has sought to crack down on leaks to media by his own team in a secret meeting - details of which were promptly leaked to media.
The fiery Mr Spicer has increased security measures, including random checks on staffers' private and government-issued phones, Politico reports.
An unnamed source said Mr Spicer was unhappy with information which had been passed to media from a planning meeting with around a dozen communication staff last week.
He brought the group back together to vent his frustration that private conversations were ending up in unflattering news stories.
It is part of an ongoing offensive against the media, with Mr Spicer last week banning a number of US mainstream media outlets including CNN, The New York Times, the LA Times and BuzzFeed, from an off-camera press briefing in his office.
President Donald Trump has also railed against the news media, calling them the "enemy of the American people" - but is reported to spend much of his time watching television news.
One source told Politico that at the "emergency meeting", staff were told to put their phones on a table for a "phone check".
Mr Spicer sought legal advice from White House lawyer Don McGahn before holding the meeting, and lawyers were present during the check.
Staff were warned using encrypted apps like Confide and Signal was a breach of the Presidential Records Act, sources said.
They were also told there'd be problems if news of the phone checks and the meeting about leaks were leaked.
Mr Trump stepped up his attack on the news media at the weekend during his speech at the Conservative Political Action Conference.
"I want you all to know that we are fighting the fake news. It's fake, phony, fake.
"A few days ago, I called the fake news 'the enemy of the people', and they are. They are the enemy of the people because they have no sources. They just make them up when there are none."