US president-elect Joe Biden is promising to distribute a coronavirus vaccine to 100 million people during the first three months of his incoming administration, pledging "100 million shots in the first 100 days".

At an event in Delaware to introduce his pandemic response team on Tuesday, Mr Biden laid out his top three priorities for the start of his new government.

It comes after the US's top infectious disease expert Dr Anthony Fauci said mass vaccination in the US could start as early as next week, following a report that suggested the Pfizer/BioNTech vaccine could soon be approved for use in the US. 

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Mr Biden, who will take over as US president from Donald Trump in January, introduced his pandemic response team and said Americans should wear masks for 100 days to prevent the transmission of coronavirus - saying he would make it mandatory on public transport and in federal buildings.

He said: "In 100 days, we can change the course of the disease and change life in America for the better.

"Whatever your politics or point of view, mask up for 100 days."

Mr Biden added that he knew it would take time for the country to recover from the virus.

He said: "My first 100 days won't end the COVID-19 virus. I can't promise that.

"But we did not get into this mess quickly. We're not going to get out of it quickly. It's going to take some time."

Meanwhile, President Donald Trump hailed the anticipated approval of the vaccine at a summit of the Covid-19 vaccination programme 'Operation Warp Speed' taking place at the White House.

The US has recorded more than 15 million cases so far and 285,000 deaths, according to Johns Hopkins University research.

Mr Trump also threatened to use the Defense Production Act - which allows the president to push industrial production of key products for reasons of national security - to ensure Americans receive the vaccine before it is exported elsewhere.

He said: "If necessary, we'll invoke the Defense Production Act, but we don't think it will be necessary.

"If it is, it's a very powerful act, as you know, because we've used it very, very successfully."

Mr Biden was not invited to attend the summit, to which Mr Trump said: "We're going to have to see who the next administration is."

He said: "We won in those swing states and there was terrible things that went on. But whichever the next administration is will really benefit by what we have been able to do.

"Hopefully the next administration will be the Trump administration."