BARCELONA, Spain (AP) — At 10:00 p.m. each night, Barcelona's professional crime fighters become wet blankets in uniforms.

Police officers fan out across the coastal city in northeastern Spain to break up clandestine parties and to clear the streets of young adults drinking alcohol, enforcing a nationwide curfew the Spanish government ordered to slow down the spread of coronavirus.

Associated Press journalists accompanied officers from the Mossos d’Esquadra, the police force for Spain’s Catalonia region, on curfew patrol. Compared to the killings, bar brawls or domestic violence calls the officers are used to handling, busting people for being out after hours is easy work.

Yet for European nations battling the resurgence of COVID-19, the assignment is critical.

“These measures save lives,” Catalonia police chief Eduard Sallent said. “We are enforcing a measure that is meant to prevent deaths and the collapse of our health care system.”

Without tourists around to clog Barcelona’s Ciutat Vella, the old town area known for its buzzy late-night scene, patrol cars weaved through labyrinth-like alleys in search of scofflaws with bottles of booze in hand. Officers looked past homeless people and the occasional dog walkers.

They focused on spotting youths who had sneaked out to share a bottle, since the city's bars and nightclubs closed completely due to the virus, while also watching for anyone who might use the unusually empty streets as an opportunity to loot stores.

Uniformed officers, with some help from plainclothes agents, checked the identities of the people they found out and about and told them to go home. Most obeyed promptly.

Some decided to make a run for it. Officers chased them down and searched them. Young men who resisted were pushed to the ground and briefly handcuffed. One inebriated woman screamed about her rights being violated. Those under 18 were taken to the police station to be retrieved by parents.

Spanish officials cited the Spanish youth custom of gathering on park benches to drink cheap liquor mixed with soft drinks — a practice called “botellón,” Spanish for “big bottle” — as a potential source of infections when Spain first emerged from its strict spring home confinement.

Some of the outdoor get-togethers can reach the level of a “macrobotellón" — mega-big bottle — and attract hundreds of participants. With face masks off and social distance reduced to inches, the partiers are easy targets for the virus.

Catalonia’s regional interior minister, Miquel Sàmper said declaring a curfew across Spain on Oct. 25 was unavoidable after some groups ignored calls to keep personal contacts and opportunities for exposure to a minimum.

“The prohibiting of night-time movement has one goal,” Sàmper said. “For weeks, we have said that no one should go out at night, or meet with several people, or consume alcohol at these parties called ‘botellón.’ But it is obvious from images we have all seen that we have not been successful."

Over 7 million confirmed COVID-19 cases and over 250,000 virus-related deaths have been reported across Europe since the start of the pandemic. In recent days, European nations from Britain to Italy have reinstituted restrictions ranging from reduced business hours and curfews to partial or near-total lockdowns to control the surge of infections sweeping the continent.

The conflict between reining in personal desires for the greater public good or giving in to individual pleasure is at the heart of Europe's renewed struggle against the virus.

Spain isn't the only place where hedonistic tendencies at night are being blamed. A big spike in cases in the northern Greek region of Serres was attributed to a party held to welcome first-year university students.

Residents in Marseille, France, alerted police to music from a nightclub that should have been empty due to virus restrictions but instead kept the party going.

On Saturday, police in London discovered a rave attended by 1,000 people. British police warned that properties rented on Airbnb and other short-term services were being used as pop-up party venues.

In August, police in Scotland broke up a party attended by more than 300 people at a mansion near Edinburgh. The owners said on Facebook that the young man who booked the house had seemed “very pleasant” and they were shocked to be told by a neighbor that “there was a huge rave and police were in attendance.”

Dozens of students have been fined for organizing illegal gatherings, including four undergraduates in the central England city of Nottingham who received the maximum 10,000 pound ($13,000) penalty after police broke up a house party.

“The very last thing we want to be doing as police officers is to be issuing these fines, but we have a responsibility to enforce the law and to keep people safe,” Nottinghamshire Police Assistant Chief Constable Kate Meynell said.

In Spain, most of the enforcement effort has involving nudging stragglers indoors after curfew. But there have been some extravagant exceptions.

Police raided a brothel in the autonomous community of La Rioja four times in eight days last month for violating health codes designed to control infections. The owner could be fined nearly 100,000 euros ($116,000).

In Madrid, police stopped the filming of a 50-person orgy. They said a pornographer arranged the event by making an open casting call with a pamphlet titled “Public Health Crime.”

The weekend before Spain’s curfew took effect, police in Madrid also busted over 300 parties that violated a prohibition on get-togethers of more than six people. Even with the curfew in place, police broke up over 100 such gatherings in apartments and 22 “botellones” on Friday night alone.

Madrid officials say 30% of the country's new confirmed infections are in people ages 15-29 and that 80% of all known infections happen in groups of family members or friends.

Madrid’s regional vice president, Ignacio Aguado, pleaded with young people to consider the consequences of their good times.

“The party you go to today can become the funeral of your father or grandfather in seven days or less," he said.

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Jill Lawless contributed from London.

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