The recent surge in US cases has led some states to tighten restrictions again.
The US reported its highest one-day increase in new COVID-19 cases on Thursday as authorities across Europe urged people to respect bans on public gatherings following a string of illegal parties.
According to Johns Hopkins University, 39,972 new cases of COVID-19 were recorded in the US on June 25, the highest daily number observed in the country so far.
The US is the most severely-hit country in the world with more than 2.4 million confirmed infections and over 124,000 deaths recorded.
The recent surge in cases has led some states to tighten restrictions again.
In Florida, which registered a record 9,000 new cases on Friday, bars are now banned from serving alcohol while in Texas, Governor Greg Abbott has paused reopening plans.
Bars that make half of their income from the sale of alcohol are required to close at midnight on Friday while restaurants may remain open but a reduced capacity.
In Europe, authorities are calling on people to respect social distancing rules and bans on public gatherings as summer temperatures send people out in their droves.
Police in London warned on Friday that thousands of officers would be deployed across the weekend to shut down unlawful music events attracting large crowds.
"We have seen some large numbers of people completely flouting the health regulations, seeming not to care at all about their own or their families' health and wanting to have large parties," Commissioner Cressida Dick said.
"It is hot. Some people have drunk too much. Some people are just angry and aggressive and some people are plain violent," she added, deploring that officers were targeted on Thursday evening while breaking up illegal raves across the British capital.
The warning comes after authorities in Bournemouth, a coastal town some 160 kilometres south-west of London, declared a major incident on Thursday after thousands of people flocked to the beach on what was the hottest day of the year so far.
Local Council leader Vikki Slade said she was "absolutely appalled" at the scenes witnessed on local beaches.
"The irresponsible behaviour and actions of so many people is just shocking and our services are stretched to the absolute hilt trying to keep everyone safe."
'Nobody leaves and nobody enters'
Tensions between police and revellers were also seen in Paris on Sunday as thousands took to the streets of the French capital to celebrate the Fete de la Musique. France, which began to ease lockdown restrictions on May 10, continues to ban gatherings of more than 10 people.
In Portugal, Prime Minister Antonio Costa announced on Thursday that parts of the greater Lisbon area will once again be confined to their homes from July 1 until at least July 14. People will only be allowed to leave their home to buy essential goods and to go to work while gatherings of more than five people will be prohibited.
Meanwhile, in Italy, the army was sent in to guard an apartment complex in Mondragone, a seaside town about 50 kilometres northwest of Naples, to ensure residents respect a quarantine order.
Some 43 or the 700 residents, including Bulgarian seasonal farmworkers, have tested positive to COVID-19.
Reports that some of the Bulgarians had fled from the complex sparked anger in the town.
Vincenzo de Luca, President of the Campania region, told reporters on Friday that the 19 people who had run away had been tracked down and tested negative.
"The complex must be kept in ``rigorous isolation," De Luca said, stressing: "that means that for 15 days, nobody leaves and nobody enters".
It comes after the World Health Organisation's European office warned that an increase in weekly cases was recorded in Europe last week for the first time in months.
"Thirty countries have seen increases in new cumulative cases over the past two weeks. In 11 of these countries, accelerated transmission has led to very significant resurgence that if left unchecked will push health systems to the blink once again in Europe," Dr Hans Henri P. Kluge, WHO regional director for Europe, said in a statement.
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