British nationals have been advised against all but essential international travel for 30 days, as the UK tries to tackle the coronavirus outbreak.
Speaking in the House of Commons, Foreign Secretary said the Covid-19 pandemic was the "worst public health crisis for a generation".
It comes as European football's governing body, Uefa, ruled this year's Euro's would be pushed back until 2021.
Mr Raab told MPs said: "With immediate effect I have taken the step to advise British nationals against non-essential travel globally for an initial period of 30 days, and of course subject to ongoing further review.
"The decision has been taken based on the domestic measures taken here in the UK, alongside the changes to border and other restrictions which are now being taken by countries right around the world."
Repatriation flights on commercial airlines were being arranged where possible to get British citizens home, Mr Raab added.
The move comes as the confirmed number of UK coronavirus cases rose on Monday to more than 1,500 and 58 deaths. Italy, France and Spain have imposed partial or full lockdowns to curb the spread of the disease.
Explaining the advised travel restrictions, Mr Raab said: "The speed and the range of those measures across other countries is unprecedented, some of those decisions are being made without notice.
"In some countries, even in countries or particular areas where there haven't yet been any reported cases of Covid-19 local authorities are nonetheless imposing restrictions on movement and again doing so with little or sometimes no notice."
The Foreign Office is not currently advising British people to immediately return to the UK if they are overseas, except from a few specific countries detailed in travel advice.
But British travellers are urged to bear in mind the prospect of flights being cancelled at short notice or additional restrictions being imposed by the local authorities.
Mr Raab added: "FCO (Foreign and Commonwealth Office) teams around the world are working urgently to ensure that governments have sensible plans to enable the return of British and other travellers, and crucially, to keep borders open for a sufficient period to enable returns to take place on commercial flights wherever that's possible.
"Following today's change in travel advice, British nationals who decide that they still need to travel abroad should do so fully aware of the increased risks of doing so and that obviously includes the risk that they may not be able to get home if travel restrictions are subsequently put in place that they hadn't anticipated."
Shadow foreign secretary Emily Thornberry asked Mr Raab to give clearer guidance about what essential travel means for Britons.
She said: "Across the world there are tens of thousands of British nationals in the same position as Thomas and all with the same message for the British Government - help bring us home, as far as we're concerned, our travel is essential.
"The Government cannot keep passing the buck to others, especially when it comes to repatriation. Yes it's difficult, yes it's expensive, but that is the nature of the crisis that we face."
Mr Raab's measures come after the European Union announced plans for a 30-day ban on non-residents entering the bloc, restrictions that are not expected to apply to Britons.
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