All passengers who were on a flight to Wales from a Greek island have been told to self-isolate after some on board tested positive for coronavirus.
Health officials say seven people from three different parties on Tui flight 6215 from Zante to Cardiff on Tuesday have tested positive for Covid-19.
Public Health Wales (PHW) is contacting the 193 passengers and crew on board.
It comes as a group of people from Plymouth tested positive for the virus after returning from Zante on Monday.
"Cardiff and Vale test, trace, protect and Public Health Wales have identified at least seven confirmed cases of Covid-19 from three different parties who were infectious on Tui flight 6215 from Zante to Cardiff on 25 August," said Giri Shankar of PHW.
"As a result, we are advising that all passengers on this flight are considered close contacts and must self-isolate."
"These passengers will be contacted shortly, but meanwhile, they must self-isolate at home as they may become infectious, even without developing symptoms."
Image copyright Getty Images Image caption Zante is a popular tourist destination for holidaymakers from the UKDr Shankar, PHW's Covid-19 incident director, said the 187 passengers and six crew on board the three-and-a-half hour flight from Zakynthos to Cardiff Airport on Tuesday that has symptoms "should book a test without delay".
There were 1,715 new coronavirus cases - and one death - reported in the UK on Sunday - the highest number since 4 June.
While no new deaths with coronavirus were reported in Wales on Sunday, 56 cases have been confirmed by PHW.
The seven cases on board the Tui flight are included in the 12 new cases reported in the Cardiff and Vale University Health Board area.
Tui said all passengers comply with Covid protocols "for the duration of their flight" including wearing face masks.
The travel operator added their aircraft have "state-of-the-art, hospital standard air filtering system", are deep cleaned after every flight and "fully disinfected at least once every 24 hours" in accordance with European Union Aviation Safety Agency (EASA) guidelines.
"The safety and well-being of passengers and crew is our highest priority and we operate in line with EASA guidelines," said a Tui spokesperson.
Image copyright Cardiff Airport Image caption Cardiff Airport, bought by the Welsh Government in 2013, is Wales' busiest airportCardiff Airport, which is owned by the Welsh Government, said it is working closely with airlines to "facilitate passenger travel throughout this challenging time for the industry".
"Tui is taking every necessary measure following today's report, said Spencer Birns, Cardiff Airport's interim chief executive.
"Cardiff Airport is closely following guidelines set out by Public Health Wales, FCO and UK Government and has already taken a number of measures to ensure the safety and security of our team and customers, which is our number one priority."
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