The United States is not the only country watching anxiously as coronavirus cases spike.
Britain is poised to shutter individual towns in the event of a rise in confirmed cases. And the government has already locked down the English town of Leicester, where textile factories may be behind an alarming jump in infections, just as the rest of the country celebrated the easing of restrictions.
Serbia reimposed a lockdown Friday as cases began to mount. Last month, neighboring Croatia reinstituted mandatory two-week self-isolation for travelers arriving from other Balkan countries. Bulgaria extended its state of emergency until July 15 and has made mask-wearing mandatory inside stores and public buildings.
Following new outbreaks, Portugal renewed coronavirus restrictions on the capital, Lisbon, and the Spanish government has moved quickly with restrictions on parts of northeast Spain to try to tamp down local spikes.
Some government officials say the biggest problem is persuading the public to observe social distancing rules and wearing masks. The easing of lockdowns and the reopening of economies do not mean caution should be jettisoned, they say.
Underlining their appeals for people to remain cautious and vigilant is an exasperation with egregious recklessness, prompting officials in some countries to question whether their citizens have the discipline or sense of civic responsibility to be trusted.
In Britain, police expressed their frustration with maskless crowds converging outside bars and restaurants in some towns, including in central London. Last Saturday, the first day that bars reopened in England after the coronavirus shutdown, police described the close-quarters drinking and shoulder-to-shoulder socializing as "absolute madness."
"A predictably busy night confirmed what we knew, alcohol and social distancing is not a good combination," tweeted John Apter, chairman of the Police Federation of England and Wales.
Sgt. Richard Cooke of the West Midlands police tweeted, "Just got home after a long shift, late shift peppered with pub fights, domestic violence & drunken, drugged up fools. If today was anything to go by the second wave won't be long in the making!"
Rafal Liszewski, a store manager in the London district of Soho, told reporters that on Saturday, "Everything got out of control. And by 8 to 9 p.m., it was a proper street party, with people dancing and drinking. Barely anyone was wearing masks, and nobody respected social distancing," he said.
Liszewski added, "To be honest, with that many people on one street, it was physically impossible" (to social distance).
Beaches have also seen swarms of people. In the English coastal town of Bournemouth, Mayor Vikki Slade said recently she was "absolutely appalled at the scenes witnessed on our beaches."
Britain has not been alone in seeing months of lockdown giving way to impromptu parties, illicit raves and illegal parties, hastily organized on social media and held in parks and industrial estates.
In Portugal, a ban in Lisbon on gatherings of more than five people was instituted amid reports of illicit parties attracting thousands of young revelers. Portugal had been hailed as one of Europe's coronavirus success stories. The government's swift response was credited with keeping the country's death toll to well under 2,000. But in recent weeks, cases have soared. Parties have proven fertile for the virus - 76 new cases were linked to a birthday celebration in The Algarve.
"After doing everything right, we're not going to ruin it now," Portuguese Prime Minister Antonio Costa said, as he banned drinking in public places and prohibited restaurants from serving alcohol after 8 p.m. Germany, France and Spain have all been worried about block parties and raves.
The World Health Organization warned that around 30 European countries have reported new case surges in the past two weeks, and epidemiologists said the trajectory is alarming in 11 countries.
Spanish officials, who recently fined Belgium's Prince Joachim $11,700 after he broke the country's quarantine rules to attend a party in southern Spain, fear that people will not be able to resist the allure of the country's ingrained culture of summer fiestas - as hundreds did recently in a spontaneous gathering in the Menorcan city of Ciutadella to mark the day of local Saint Joan.
Along with officials, infectious disease experts blame signs of a resurgence on the negligence of the public, with too many people ignoring orders to wear masks and keep their distance. But critics in several European countries fault officials, saying governments have been giving mixed signals in their eagerness to restart economies and end lockdowns, and have issued at times contradictory and confused instructions.
They say governments seem to be positioning themselves to blame the public for a coronavirus resurgence.
David King, a former chief scientific adviser to the British government, has criticized the lockdown easing as over-hasty.
"We need to look at the fastest route out of COVID-19, and that is not the current route," he said.