The White House Correspondents Association has slammed CNN for providing no access to its pool reporters inside the room where President Joe Biden and his predecessor Donald Trump engaged in the first of the three presidential debates here, asserting that it diminishes a "core principle" of the coverage.

CNN is the host of the first of the three presidential debates in Atlanta.

Scores of media outlets from across the country have gathered to watch the debate, which unlike in the past has no audience. Media have access only to the spin room.

“Tonight’s debate will have no audience present and includes format rules that can silence candidates’ microphones. We don’t know how this will play out in real-time," Kelly O’Donnell, president of the White House Correspondents’ Association wrote in a strongly-worded letter to CNN.

"A pool reporter is there to observe what is said and done when microphones are off or when either candidate is not seen on camera but may speak, gesture, move, or engage in some way,” O’Donnell said on Thursday.

A pool of reporters always travel and are with the President during his official working hours and report to the rest of the members of the WHCA.

CNN is also a member of the WHCA, she said.

“WHCA is deeply concerned that CNN has rejected our repeated requests to include the White House travel pool inside the studio. Through conversations and advocacy, we urged CNN to grant access to at least one print pool reporter for the duration of the debate,” the letter said.

“WHCA has been informed that one print reporter will be permitted to enter the studio during a commercial break to briefly observe the setting. That is not sufficient in our view and diminishes a core principle of presidential coverage," O’Donnell wrote.

"The White House pool has a duty to document, report and witness the president’s events and his movements on behalf of the American people,” the letter said.

“The pool is there for the 'what ifs?' in a world where the unexpected does happen. A pool reporter is present to provide context and insight by direct observation and not through the lens of the television production. A pool reporter is an independent observer whose duties are separate from the production of the debate as a news event,” she explained.

Asserting that pool reporter works on behalf of the entire White House press corps, she said that their reports are an important part of the historical record.

She said that since the pool is screened by the US Secret Service and travels with the president on Air Force One, there is no security issue.

"The Biden campaign told WHCA it supports our request. The Trump campaign told WHCA it would not oppose the inclusion of the White House pool reporter. The Trump campaign has a separate press corps,” wrote the WHCA president.

O’Donnel said for weeks, WHCA has advocated for the inclusion of the White House travel pool inside the studio for the presidential debate.

“Our work has included outreach to the White House, the campaigns of both President Biden and former President Trump and the debate host network CNN,” she said.

“We appreciate that CNN is providing a television feed of the debate to other networks, and will grant access to still photographers from various news outlets to cover the candidates inside the studio. Those are positive actions that WHCA fully supports,” she wrote.

There was no immediate reaction from CNN.

“White House reporters constantly press organisations hosting the president to allow us access wherever he goes. That's our job. The notion that we would be stiffed by a news organisation is pretty mind-boggling,” said Peter Baker, White House Correspondent of The New York Times.

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