Euro 2020 fans should avoid attending games if they have any COVID-19 symptoms and wear masks in stadiums allowing around 50% capacity, a European Union agency urged on Thursday, amid concern the tournament could spread infections. The European Championship, postponed last year because of the pandemic, starts on Friday for one month with 11 countries hosting games and stadiums allowing fans back. Budapest aims for full capacity while Saint Petersburg and Baku will have 50%. Amsterdam, Bucharest, Copenhagen, Glasgow, Rome and Seville will use between 25% and 45% of capacity, while Munich will use a minimum 22% capacity and London"s Wembley - which hosts the final - a minimum 25% for the initial games. The European Centre for Disease Prevention and Control estimates about half a million spectators will attend. "Should mass gathering events such as the UEFA European Football Championship take place in the absence of sufficient mitigation measures, the risk of local and pan-European transmission risk of COVID-19, including the spread of variants of concern, would increase," it said in a report. "Any person with COVID-19 compatible symptoms should not attend match or post-match events, irrespective of their vaccination status," it added, urging authorities to provide testing close to stadiums.