Team GB’s preparations for the Olympics have been plunged into chaos after six athletes and two staff members from the athletics squad were forced to self-isolate after coming into close contact with a member of the public who had Covid-19 on their flight to Tokyo. The news, which broke late on Sunday afternoon in Yokohama after the athletes had finished training for the day, stunned officials who immediately rushed to ensure that the athletes and staff members were confined to their rooms. All eight must now pass two PCR tests over the next 48 hours before being allowed to mingle with other members of the squad again. One source described a sense of “shock” when hearing the news. But another said they had been prepared for such an incident arising, and “it would have been naive to think there were not going to be issues”. The athletes and staff have not been named but it is understood that Team GB’s biggest athletics stars – including Dina Asher-Smith, Katarina Johnson-Thompson and Laura Muir – are not affected. The news was confirmed by Team GB’s Chef de Mission, Mark England, who said those involved were not to blame for being a close contact of someone who tested positive for Covid after their flight landed in Tokyo on 16 July. “This is disappointing news for the athletes and staff but we absolutely respect the protocols in place,” said England. “We will offer them every support during this period and we are hopeful that they will be able to resume training again soon.” The British Olympic Association said that all of the group tested negative at the airport and had continued to test negative upon arrival into the country. They are under the supervision of the Team GB medical team, led by the chief medical officer, Dr Niall Elliott. Earlier the growing concern about the spread of Covid at these Games was highlighted when two South African footballers became the first athletes in the Olympic Village to test positive, further raising fears that the virus may force a number of competitors out of the Tokyo Games when they open officially on Friday. The players, Thabiso Monyane and Kamohelo Mahlatsi, as well as the video analyst Mario Masha who also tested positive on arrival, are now isolating. South Africa will face Japan in the Tokyo Stadium on Thursday. The team manager, Mxolisi Sibam,, who confirmed the news, added: “Masha and Monyane reported high temperatures and positive saliva tests, and were then taken to do the nasal test and they unfortunately tested positive for Covid-19. Mahlatsi is the latest player to go through the same process.” Sibam said the entire South African team had been quarantined while waiting for results from tests earlier on Sunday. “This unfortunate situation has made us miss our first intensive training session last night.” However, the Tokyo 2020 president, Seiko Hashimoto, has reassured athletes that organisers have “a plan in place” to respond to an outbreak in the Village. On Sunday that message was reinforced by the IOC Olympic Games executive director, Christophe Dubi, who claimed the risks of the virus running rampant in the village was “almost impossible”. “We know there is no such thing as zero-risk but at the same time the mingling and crossing of populations is very limited,” he added. “With all the measures that are in place, we keep the risk to an absolute minimum level. “What we have done since cases have appeared at the airport and in the Village is make sure they are ring-fenced, tested and do not provide a risk.” The Games, postponed for a year due to the global pandemic, are being held mostly without spectators and under tight quarantine rules, with Tokyo currently in a state of emergency. Infection rates are also rising in the Japanese capital after topping 1,000 new cases for four consecutive days.