The White House has ordered federal health officials to treat top-level coronavirus meetings as classified, an unusual step that has restricted information and hampered the U.S. government's response to the contagion, a Reuters report said, citing four Donald Trump administration officials. 

The officials said that dozens of classified discussions about such topics as the scope of infections, quarantines and travel restrictions have been held since mid-January in a high-security meeting room at the Department of Health & Human Services (HHS), a key player in the fight against the coronavirus. 

Staffers without security clearances, including government experts, were excluded from the inter-agency meetings, which included video conference calls, the sources said. 

"We had some very critical people who did not have security clearances who could not go," one official said. "These should not be classified meetings. It was unnecessary." 

The sources said the National Security Council (NSC), which advises the president on security issues, ordered the classification. "This came directly from the White House," one official said. 

The White House insistence on secrecy at the nation's premier public health organization, which has not been previously disclosed, has put a lid on certain information – and potentially delayed the response to the crisis. COVID-19, the disease caused by the virus, has killed about 30 people in the United States and infected more than 1,000 people.

HHS oversees a broad range of health agencies, including the U.S. Centers for Disease Control and Prevention, which among other things is responsible for tracking cases and providing guidance nationally on the outbreaks. 

The administration officials, who spoke to Reuters on condition of anonymity, said they could not describe the interactions in the meeting room because they were classified. 

An NSC spokesman did not respond to questions about the meetings at HHS. But he defended the administration's transparency across federal agencies and noted that meetings of the administration's task force on the coronavirus all are unclassified. It was not immediately clear which meetings he was referring to. 

"From day one of the response to the coronavirus, NSC has insisted on the principle of radical transparency," said the spokesman, John Ullyot. He added that the administration "has cut red tape and set the global standard in protecting the American people under President Trump's leadership." 

A spokeswoman for HHS, Katherine McKeogh, issued a statement that did not address questions about classified meetings. Using language that echoed the NSC's, the department said it that it agreed task-force meetings should be unclassified.

Critics have hammered the Trump administration for what they see as a delayed response to coronavirus outbreaks and a lack of transparency, including sidelining experts and providing misleading or incomplete information to the public. State and local officials also have complained of being kept in the dark about essential federal response information. 

U.S. Vice-President Mike Pence, the administration's point person on coronavirus, vowed on March 3 to offer "real-time information in a steady pace and be fully transparent."  

After days of downplaying the threat of the outbreak, Trump on Wednesday suspended all travel from Europe to the United States for the next 30 days, excluding the UK. 

The announcement came as confirmed COVID-19 cases in the U.S. rolled past 1,200 and the World Health Organization declared the outbreak a pandemic.