The Foreign Office has warned against all but essential travel to the United States.
The move comes hours after Washington said a ban on UK and Irish flights to the US would be introduced because of the coronavirus outbreak.
A Foreign Office spokesperson said: ”We are advising against all but essential travel to the USA following the US government announcement imposing restrictions on travel from the UK.”
Britons will be added to America’s ban on travellers from Europe from 4am GMT on Tuesday.
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People with journeys planned are advised to check with their airline and tour operator.
Those already in America are also recommended to stay in contact with their travel company and airline.
Acting homeland security secretary Chad Wolf said the ban had been extended because of the growing COVID-19 outbreak in the UK, where 35 people have died.
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Downing Street said on Saturday night that Boris Johnson had spoken to Mr Trump but did not confirm if they had discussed the ban.
America’s 30-day suspension on passenger flights from the Schengen Area of mainland Europe started on Friday – but the UK and Ireland were not initially included.
President Trump blamed the European Union for not acting quickly to address the outbreak and said US clusters were “seeded” by European travellers.
However, he said the UK was doing a “good job” on handling the situation
The ban was criticised by the EU, which said it was a “unilateral decision” taken “without consultation”.
Meanwhile, the coronavirus continues to cause havoc for international travel and the world’s airlines.
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Ryanair has announced major cuts to its Spanish flights because of the lockdown in the country.
“Ryanair Group Airlines (including Buzz and Lauda) has been forced to severely reduce flights to/from Spain, the Balearic Islands and Canary Islands from 24:00 Sun 15 Mar until 24:00 Thurs 19 Mar,” said a statement.
The chairman of Virgin Airlines is also set to tell Boris Johnson the UK airline industry needs billions to avert a catastrophe.
Morocco has suspended all international passenger flights to and from its airports. The country has had 28 coronavirus cases including one death.
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