EUROPE faces a new wave of Covid infections as the WHO warns Euro 2020 fans could be super-spreaders of a new "Delta-plus" strain.
Top health officials in Russia warn spectators could be helping to spread the new variant after many tested positive on return from matches.
Covid-19 infections in Europe increased 10 per cent in one week, the World Health Organization says.
Russia witnessed its deadliest 72 hours in weeks, registering 672 deaths and 23,453 new cases on Thursday alone.
Euro 2020 host city St Petersburg recorded 115 deaths just hours before Spain and Switzerland were set to kick-off their group stage match at Gazprom Arena.
Although authorities are pointing to a slow vaccine rollout, new variants and increased social mixing as reasons for the latest spike, many see the Euros as the match that lit the tinderbox.
Germany's Interior Minister Horst Seehofer branded European football's governing body, Eufa, "irresponsible" for the letting the games go ahead.
"I cannot explain why UEFA is not being sensible... I suspect it is due to commercialism," he told reporters.
UEFA says local authorities at each stadium are responsible for deciding the number of fans allowed inside.
Regardless, capitals that have chosen to host Euro 2020 matches such as London have seen an increase in infections since the competition began last month.
In the UK, authorities clocked another 27,989 cases - the highest number since January.
Meanwhile, Portugal imposed a night-time curfew on Lisbon, Porto, and other municipalities on Friday.
Spain has seen an uptick in infections among people in their 20s while Germany expects the Delta variant to account for over 70 per cent of cases this month.
This comes after the Slovakian football team were rocked by a coronavirus scare among their squad just hours before their game with Sweden on June 18.
Lazio defender Denis Vavro, 25, and one member have staff both returned positive tests for Covid-19.
Slovakia chief Stefan Tarkovic claims his team did all the could to avoid the spread of infection and ended up playing Sweden.
Tarkovic revealed: "We started to work with the Russian public health authorities and started to apply the corresponding Uefa protocol.
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"So we took all the steps to avoid the spread of the infection."
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That weekend, Portugal was also rocked by the news Joao Cancelo had tested positive for Covid.
The Manchester City star was ruled out of the Euros, replaced by Diogo Dalot.