The White House has blocked a number of news outlets from covering a question-and-answer session with spokesman Sean Spicer held in place of the daily press briefing.

Media organisations including The New York Times, CNN, Politico and Al Jazeera were blocked from joining the informal, on-the-record, off-camera press briefing on Friday, referred to as a "gaggle".

Some of the blocked outlets, including CNN, have been singled out by President Donald Trump as sources of "fake news".

Spicer invited only a pool of news organisations that represents and shares reporting with the larger press corps.

Journalists from several right-leaning outlets were also allowed into Spicer's office, including the website Breitbart News, whose former executive chairman, Steve Bannon, is Trump's chief strategist.

When additional news organisations attempted to gain access, they were not allowed to enter.

Al Jazeera's Kimberly Halkett, reporting from the White House, was among those asked to leave.

"This is really the latest in an ongoing media war with this White House," she said.

"Some of those who are concerned about this are outlets that have been accused by the White House of reporting unfavourably, namely that they reported that the White House recently tried to deploy the FBI to counter some negative reporting with regard to whether or not there had been contact between the White House and Russian officials."

Typically, the daily briefing is televised and open to all news organisations credentialed to cover the White House.

The Associated Press and Time magazine chose not to participate in the gaggle after Spicer restricted the number of journalists present.

'Don't need everything on camera'

Spicer said the White House held a gaggle rather than an open briefing because Trump made a major speech earlier in the day.

"Our job is to make sure that we're responsive to folks in the media," he said during the briefing. "We want to make sure we answer your questions, but we don't need to do everything on camera every day."

READ MORE: Trump declares media 'the enemy of the American people'

In a statement, White House Correspondents' Association President Jeff Mason said the group was "protesting strongly" against how the gaggle was handled by the White House and that the issue would be discussed further with officials.

Speaking to Al Jazeera, Mason added that press access to the White House since Trump took office in January has been "good".

"There's some irony to that statement because the tone set by President Trump about the media, of course, has been very negative," he said, "but we have had many opportunities to ask questions, both of the president and Sean Spicer, his press secretary, and to see and take pictures basically of how this White House governs. That is a positive thing and a trend we hope will continue."

After The New York Times was barred from attending the gaggle, its executive editor, Dean Baquet, said that "nothing like this has ever happened at the White House in our long history of covering multiple administrations of different parties."

CNN described the move as an "unacceptable development by the Trump White House".

"Apparently this is how they retaliate when you report facts they don't like. We'll keep reporting regardless," the broadcaster said in a statement.

The Committee to Protect Journalists also condemned the move by the White House.

"We are concerned by the decision to bar reporters from a press secretary briefing," CPJ Executive Director Joel Simon said in a statement. "The US should be promoting press freedom and access to information."