WASHINGTON (REUTERS) - The head of the US Centres for Disease Control and Prevention (CDC) testified on Thursday (March 12) on Capitol Hill that public health officials discussed coronavirus information in classified rooms on occasions "too numerous to count", though he said the information wasn't treated as classified.

On Wednesday, Reuters reported that the White House ordered federal health officials at the Department of Health and Human Services (HHS), the nation's premier health agency, to treat top-level coronavirus meetings as classified, citing four Trump administration officials.

The officials said that dozens of such discussions have been held since mid-January in a high-security meeting room at HHS, which oversees the CDC, and that staff without security clearances have been excluded.

After the story was published, the National Security Council spokesman John Ullyot e-mailed Reuters on Wednesday evening, saying, "The White House has never ordered any agency 'to treat top-level coronavirus meetings as classified'," as the story alleged.

"This story is fake news," he wrote.

Asked about the Reuters report on Thursday, Dr Robert Redfield, the director of the CDC, told the House Oversight and Reform Committee of the meetings: "We're holding them in a classified room, but the nature and the content of those conversations are not classified."

The Vice-President's office e-mailed a joint statement from HHS Secretary Alex Azar and National Security Adviser Robert O'Brien on Thursday saying they were "perplexed" by the Reuters story, saying that task force meetings convened by Vice-President Mike Pence take place in the White House Situation Room and are unclassified.

However, the Reuters story was not about the Pence task force, which he began to lead at the end of February.

"We stand by our story," a Reuters spokesman said on Thursday.

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The Reuters story focused on meetings at HHS that sources said were held in a SCIF (sensitive compartmented information facility).

SCIFs are intended to be used for classified matters and include restrictions on attendees such as prohibiting most cellphones.

The sources, who all spoke on condition of anonymity, said they could not describe the interactions in the SCIF because they were classified. But they said topics included the scope of the outbreaks, quarantine issues and travel restrictions.

A spokesman for Republican Senator Chuck Grassley, from Iowa, said on Thursday that Mr Grassley's office had contacted the White House to ask about the Reuters' report because he was concerned about the potential over-classification of information, an issue he had raised previously.

"Federal health experts need to be able to access all Intelligence Community information that could help combat this pandemic," said the spokesman, Mr Michael Zona.

Mr Kel McClanahan, a Washington lawyer who specialises in national security law and classification matters, said that if the practice was to hold these meetings in a SCIF, block certain people who lacked security clearances from attending and prevent attendees from discussing the matters with uncleared people, then "it would be classified".