Four Finns arrive in Sweden on a British plane despite the ban
The Finnish nationals were allowed to continue to Finland after the incident, which was attributed to "a misunderstanding" by the Swedish Transport Agency.
Sweden detects the first case of the new British coronavirus variant.
A British passenger plane landed on Saturday in Sweden with passengers onboard, despite a recent temporary ban for such flights from Britain, police said.
The British Airways flight had 33 passengers onboard, including 29 Swedish nationals and 4 Finnish nationals, the Svenska Dagbladet daily reported.
"We were taken by surprise," Patrik Engstrom, head of the border police told Svenska Dagbladet that broke the story.
Engstrom said that police inspected the plane when it landed at Stockholm Arlanda airport and had not expected any passengers to be on the flight. However, the Swedish nationals were allowed to disembark since they are always allowed to enter Sweden.
The Public Health Agency urged the passengers to test themselves, and self-isolate. None have presented any symptoms.
The Finnish nationals, including several small children, were allowed to continue to Finland, the report said.
The incident was attributed to "a misunderstanding," a spokesman for the Swedish Transport Agency told Swedish broadcaster SVT, adding that the agency had contacted the airline, its British counterpart and clarified the rules to avoid a repeat.
Sweden recently introduced a ban for passenger flights from Britain effective up to and including New Year's Eve. The ban did not effect freight planes and ambulance flights, and there were exceptions for urgent family matters.
Earlier, Sweden said that it has recorded its first case of the new, apparently more transmissible variant of the coronavirus that appeared in Britain.
A case of the new strain found
A traveller who recently arrived from Britain for the Christmas holidays has tested positive for the new mutated strain, Sara Byfors of the Public Health Agency told a regular press conference.
Other members in the traveller's household have tested negative, added Signar Makitalo, infectious disease physician with the region of Sodermanland, near Stockholm.
Makitalo said the traveller had been "extremely careful" and sought to limit all risks. The test result was from December 21, and the new strain was confirmed on Saturday.
The traveller - who was not identified by gender, nationality or age - had followed recommendations and self-isolated on arrival in Sweden.
"We cannot rule out that there are other cases," he said.
Arrivals from Britain were advised to self-isolate for seven days.
"We are collecting samples from everyone who has arrived from Britain since October. This week we urged everyone who has travelled from Britain to test themselves," Byfors added.