Video report by ITV News Washington Correspondent Emma Murphy
Joe Biden has warned Americans they are entering the “toughest and deadliest period” in their efforts against coronavirus, as the newly sworn-in president unveiled a raft of new measures aimed at combating the disease.
On his first full day in office, Mr Biden signed 10 pandemic-related executive orders as the US aims to step up its efforts against Covid-19.
While many forms of transport, including airlines and train companies, required people to wear masks, a new federal law has been introduced making it a legal requirement for travellers to wear face coverings.
Emma Murphy has more analysis of President Biden's first move to handle the pandemic:
This will apply to airports, planes, ships, intercity buses, trains and public transportation.
Travellers from abroad must now provide a negative Covid-19 test before departing for the US and must now quarantine upon arrival.
And Mr Biden has also set the target of administering 100 million vaccine shots in his first 100 days in office.
Jeff Zients, the White House official directing the national response, said: “We need to ask average Americans to do their part.
“Defeating the virus requires a coordinated nationwide effort.”
President Biden acknowledged the task facing the country in his inaugural address, saying: “We are entering what may well be the toughest and deadliest period of the virus.”
Mr Zients said Mr Biden will not follow through on a Trump administration plan to penalise states lagging in vaccination by shifting some of their allocation to more efficient states.
“We are not looking to pit one state against another,” he said.
Mr Biden has also set a task of getting schools to reopen safely, but administration officials stressed their reopening depends on increased testing,
“We do not have nearly enough testing capacity in this country,” Mr Zients said.
“We need the money in order to really ramp up testing, which is so important to reopen schools and businesses.”
Efforts to reopen the country will large depend on whether Congress will pass the $1.9 trillion package proposed by Mr Biden, which includes numerous layers including a $1,400 direct payment to people, a $15 minimum wage and state aid to local governments.
But the proposals are likely to face some opposition from Republicans, who feel the measures are unnecessary for dealing with the medical emergency.