Nearly four months after it was suspended, UEFA's plans to complete the Champions League in Portugal are once again under threat from the coronavirus, even if the organisers themselves insist there is "no Plan B". UEFA president Aleksander Ceferin claimed Tuesday following a meeting with Portuguese Prime Minister Antonio Costa that there was no need to make alternative arrangements to the planned "final eight" straight knockout format for the quarter-finals onwards, with all games set to take place in Lisbon. Costa himself said that "all measures are being taken to ensure that we will host this tournament in a safe and secure manner". However, the ongoing health situation in Portugal casts some doubt on those pronouncements. On Wednesday, lockdown restrictions were reimposed on 19 neighbourhoods across the northern periphery of Lisbon where COVID-19 outbreaks persist. The restrictions concern some 700,000 people and will remain in place for at least two weeks. With an average of 321 per day, the number of new cases being recorded in Portugal grew by a third in June compared to the previous month. The majority of new cases are in the Lisbon area, and it is the capital which is due to host the latter stages of the Champions League, starting with the quarter-final on August 12 and concluding with the final on August 23. Alarm bells may be ringing within European football's governing body, especially as the Champions League was suspended in March and remains frozen in the last-16 stage, which has not been completed. Costa has done his best to reassure Ceferin and insisted in an interview with Spanish daily La Vanguardia that the lockdown measures "do not concern the centre of Lisbon, where the Champions League will be staged". However, the locked down neighbourhood of Santa Clara borders that of Lumiar, the area in which the Estadio Jose Alvalade is situated. The home of Sporting Lisbon is scheduled to share hosting of the Champions League matches with Benfica's nearby Estadio da Luz. - 'Proportionate measures' - Costa's comments have not gone down well with local residents. "The Prime Minister seems worried about the situation in Lisbon, without doubt because of the Champions League. It is not worth pretending that the problem does not exist, because it also exists in Lisbon," Goncalo Caroco, deputy mayor of nearby Loures, told AFP. Atletico Madrid, Paris Saint-Germain, RB Leipzig and Atalanta all qualified for the quarter-finals before the competition was suspended in March and UEFA was eventually forced to come up with a new format to finish it. The remaining last 16, second legs will see Juventus face Lyon, Manchester City take on Real Madrid, Bayern Munich face Chelsea and Barcelona come up against Napoli. It is hoped those matches -- set for August 7 and 8 -- will not need to be played on neutral ground but they could also be moved to Portugal, with UEFA standing by to spread the matches around the country, in Lisbon as well as in the northern cities of Porto and Guimaraes. A fortnight ago, when the format was announced by UEFA, Ceferin expressed hope that some fans might be able to attend the matches. That now seems improbable. "In terms of the situation with the pandemic, obviously it is a no," said Portugal's Health Minister, Antonio Lacerda Sales, earlier this week. "We don't know how the pandemic is going to evolve and we will continue to take proportionate measures. We can't anticipate the future, but at this moment of course not," he elaborated. If the situation continues to deteriorate, the competing teams would perhaps also have second thoughts about travelling to Lisbon.