Germany has become the latest European country to ban most travellers from Britain, to try to slow the spread of the Omicron variant.
German nationals and residents will still be allowed to enter from the UK.
They must have a negative test and quarantine for two weeks, regardless of whether they have been vaccinated.
The measures take effect from Sunday evening and France has already introduced similar curbs as coronavirus infections surge in Britain.
The Robert-Koch-Institut - a federal health agency - announced the new rules as it classified the UK as a virus variant area of concern, the highest Covid risk level.
Denmark, France, Norway and Lebanon have also been added to Germany's high risk list and travel from those countries will also be restricted.
The move comes after another 90,418 daily Covid cases were reported across the UK on Saturday - following days of record highs.
London Mayor Sadiq Khan declared a "major incident" in the capital on Saturday due to sharp rise in cases. On Saturday, 26,418 new cases reported - the highest number since the start of the pandemic.
Scientific advisers have warned that England's hospital admissions could reach 3,000 a day without further restrictions.
Although the number of new confirmed coronavirus cases in Germany is lower than in the UK, with 50,968 new cases reported on Friday, the number of deaths following a positive Covid test is rising. Germany reported 437 deaths on Friday.
German health minister Karl Lauterbach said he expected the Omicron variant to unleash a "massive fifth wave" of the pandemic.
He said Germany had to prepare for a challenge "that we have never seen in this form before".
On Saturday, Prof Lauterbach said that the "more we can push back... the better".
France is also worried about the spread of Omicron in the UK and authorities there banned UK tourists from travelling between the two countries on Saturday.
Under its new rules, UK citizens now need a "compelling reason" to enter France, with trips for tourism or business banned.
Hauliers, transport workers and French nationals are exempt.
A rush of passengers travelling to France on Friday to beat the country's ban on UK tourists led to a knock-on effect on freight traffic, resulting in long queues of lorries.
There were lengthy tailbacks on the M20 motorway in Kent heading to Dover and at the entrance to the Channel Tunnel on Saturday.
Many people brought their Christmas travel plans forward to avoid the new rules.
BDST: 1601 HRS, DEC 19, 2021