Late Saturday evening, about 50 young people squeezed into a Northwest Side townhouse in Chicago to dance, drink and chat at a party, police said.

A few wore face masks, but most had shed the protective gear as they stood within inches of dozens of other partygoers. One woman filmed the lively scene and broadcast it live on Facebook.

Shortly after midnight on Sunday, Chicago police showed up at the town house’s door and sent everyone home.

“What was depicted on the video was reckless and utterly unacceptable,” Chicago Mayor Lori Lightfoot (D) said Sunday in a tweeted statement. “While most Chicagoans are doing their part to prevent the spread of COVID-19, reckless actions like these threaten our public health and risk erasing the progress we have made.”

Cook County, where Chicago lies, has had more than 31,900 cases and 1,347 deaths as of Tuesday morning. Despite a statewide order that bans large gatherings, Chicago police have had to break up more than 5,200 groups since March 31 for defying the rules that aim to stop the spread of the virus, Chicago Police Department spokesman Luis R. Agostini told The Washington Post.

The party occurred as many states, including Illinois, are preparing to lift some of the social distancing restrictions that have closed nonessential businesses and most public spaces.

On May 1, the state’s stay-at-home rules will change slightly, allowing the reopening of some establishments including golf courses, garden centers and retail stores while also requiring people to wear masks in any public environment where social distancing isn’t possible.

Similarly, states like Georgia, Missouri and Texas have plans to open some establishments, such as restaurants and hair salons, in coming days and weeks.

Social distancing guidelines are nearing the start of a third month, and people have grown antsy after as many as eight weeks cooped up indoors in some jurisdictions. Visitors eager to enjoy the outdoors filled West Coast beaches this weekend during a heat wave in Southern California, spurring the state’s governor to chide those who failed to stay inside.

“This virus doesn’t go home because it’s a beautiful sunny day around our coasts,” Gov. Gavin Newsom (D) said Monday, after photos of crowded beaches went viral. He added that California, which adopted strict social distancing restrictions earlier than most states, is just weeks away from being able to lift the rules safely.

“Those images are an example of what not to see,” he continued, “what not to do if we’re going to make the meaningful progress that we’ve made in the last few weeks extend into the next number of weeks.”

The illicit house party, which violated the Illinois stay-at-home order in place since March 21, recalls the original source of Chicago’s coronavirus outbreak.

One person who had caught the novel coronavirus while traveling out-of-state spread it to at least 16 people by attending a funeral and a birthday party in the city. The people who contracted covid-19 had shared food, hugs and conversation with that first Chicago patient. From there, the virus spread in a church, infected a home-care worker and was passed on to several family members. At least three people infected in that early covid-19 cluster died, according to a study tracking the spread of the virus published by the Centers for Disease Control and Prevention.

Video of the weekend’s house party, which went viral on Facebook before it was taken down on Monday, frustrated local officials.

The mayor slammed the young people who stood “cheek-to-jowl” inside the small townhouse.

“Millennials aren’t children,” Lightfoot told the Chicago Sun-Times. “Millennials — many of them — are in their 20s. They’re fully functioning adults. And we expect adults to act responsibly — particularly at a time of pandemic.”

Illinois Gov. J.B. Pritzker (D) also denounced the partygoers at a news conference on Sunday, ABC7 Chicago reported.

“I want to remind everyone that by doing that, by standing together, not social distancing, many people not wearing masks, you’re literally putting everyone around you in danger,” Pritzker said. “And very importantly, all of those people are putting their families and their friends who are not there with them in danger.”

Chicago police officers returned to the home on Monday to cite the owner for disorderly conduct, Agostini told The Post.

Alderman Gilbert Villegas, who represents the Northwest Chicago district where the house party was hosted, said it was thrown by the homeowner’s adult son and was the second party at that residence in recent weeks, the Sun-Times reported.

The woman who posted the now-deleted video on Facebook defended her choice to go to the party by comparing it to venturing into grocery stores.

“Y’all go out to stores (food-4-less, wal-mart, target) and touch all type of s--- after somebody else had already touched it,” Tink Purcell wrote on Facebook. “Faith over fear god got me and mines.”