UK Prime Minister Boris Johnson has warned there are signs of a "second wave" of coronavirus in Europe, as he defended a 14-day quarantine on travellers from Spain.
He said the government had to be "swift" - and hinted at further action against other countries if necessary.
But airline Jet2 said information from the government was "contradictory and often comes with little or no notice". It comes after the Spanish prime minister called the UK's decision to change the rules for Spain "unjust". Pedro Sánchez said tourists in most regions in Spain would be safer from coronavirus than in the UK.
The UK is advising against all non-essential travel to Spain, including the Balearic and Canary Islands. It also removed Spain and its islands from the list of countries that are exempt from the 14-day quarantine rule.
The PM said it was up to individuals to decide whether they wanted to take the risk of travelling during the pandemic. "These are decisions for families, for individuals, about where they want to go," he said. Meanwhile, Germany has advised against travel to three areas of Spain.
Speaking during a visit to Nottinghamshire, Johnson said: "What we have to do is take swift and decisive action where we think that the risks are starting to bubble up again. "Let's be absolutely clear about what's happening in Europe, amongst some of our European friends, I'm afraid you are starting to see in some places the signs of a second wave of the pandemic."
It came as the UK reported a further 119 coronavirus deaths - taking the official number of fatalities so far to 45,878 - but the daily figure is typically higher due to delays in reporting deaths at the weekend. An additional 581 positive cases have also been reported across the UK, a small dip on recent days.
Asked about reports that the 14-day period could be reduced, Mr Johnson said: "We are always looking at ways in which we can mitigate the impact of the quarantine. "At the moment you have got to stick with the guidance that we are giving, we have given the guidance now about Spain and about some other places around the world."
On whether the 14-day quarantine period could be cut, transport minister Baroness Vere said the government was "looking at a range of options" including "testing people on certain days" after they arrive.
Ministers are also "certainly looking" at the idea of restrictions on travel to regions rather than whole countries, she said during an urgent question in the House of Lords.