US President Donald Trump has warned that as many as 100,000 people could die of coronavirus in the US.
Speaking at a two-hour virtual “town hall”, Mr Trump also denied that his administration had acted too slowly.
More than 67,000 people have already died with Covid-19 in the US.
But Mr Trump expressed optimism about the development of a vaccine, saying one would be ready by the end of this year – although public health experts believe it will take 12 to 18 months.
Among the experts to disagree with this optimistic estimate are Dr Anthony Fauci, the US’s top infectious disease expert, and England’s chief medical officer Chris Whitty.
Dr Fauci has previously said a vaccine will take up to 18 months to develop, while Professor Whitty said last month that the chances of having an effective vaccine or other treatment within the next year were “incredibly small”.
However, us broadcasters CNN and ABC report that the president’s intelligence briefings mentioned the coronavirus as early as 3 January.