Sweden said on Wednesday it will require foreign travellers to present a negative coronavirus test no older than 48 hours in order for them to enter the country.
"As of Saturday, February 6, foreign nationals travelling to Sweden must present a negative Covid-19 test, otherwise they will not be allowed in," Prime Minister Stefan Lofven said.
Home Affairs Minister Mikael Damberg added that the measure would run until March 31, and applies to people over the age of 18.
The government said it was acting on concerns raised by the Swedish Public Health Agency regarding the spread of new, more contagious variants of the coronavirus, including a strain initially detected in Britain.
The Public Health Agency would list which tests were valid, Damberg said.
Exemptions included urgent family reasons, employees in the transport sector or people who commute across borders for work. People in the last category were advised to test themselves on a weekly basis.
Swedish nationals or those resident in Sweden were advised to be tested before their arrival - or to be tested the same day they arrived. They should self-isolate for seven days and take a second test during that period, according to the government's advice.
Members of their households were also advised to stay at home during that period.
Sweden, a country of 10.3 million, has now registered 580,000 cases and 11,939 deaths since the pandemic began.