CHICAGO (CBS) — Busted.

Mayor Lori Lightfoot this weekend saw sun lovers violating COVID-19 safety rules – and she has since taken action and has also said more restrictions could follow.

As CBS 2’s Jeremy Ross reported Sunday night, it all started Saturday with a photo that came across Mayor Lightfoot’s Twitter account.

The number of new COVID-19 cases, and the positive test rate for the virus have been climbing steadily in Chicago and across Illinois for the past several weeks, prompting Lightfoot and Gov. JB Pritzker to caution that they might be forced to resume some restrictions that were lifted earlier this summer if new cases aren’t brought under better control.

Lightfoot sounded the alarm again on Saturday, sharing a photo on Twitter of a large crowd gathered on a lawn at Montrose Beach, with few if any masks in sight, and most people in the picture not keeping six feet away from each other, the two most basic public health measures recommended by the Centers for Disease Control and Prevention and local health departments to slow the spread of the coronavirus.

“It’s called a pandemic, people. This reckless behavior on Montrose Beach is what will cause us to shut down the parks and lakefront. Don’t make us take steps backwards,” Lightfoot wrote.

On the actual Montrose Beach, there are at times more birds – seagulls and also endangered piping plovers – than sunbathers. All of the city’s beaches have been closed since the start of the summer season due to COVID-19 concerns and they have stayed that way.

This weekend, the park adjacent to Montrose Beach was also shut down – with entrances to the area barricaded.

While foot traffic remained, most vehicle traffic was routed elsewhere due to what city leaders described as the party-turned-health-hazard seen in that photo.

“Definitely was not social distancing; a lot of people didn’t have masks on,” said Justin Schneider.

Lightfoot shut down the city’s lakefront trail, lakefront parks, and beaches in late March, along with the 606 trail and the Riverwalk, after too many people ignored her warnings to avoid large gatherings as the pandemic was in its infancy and just beginning to spike in the first wave in Chicago.

The Riverwalk reopened in mid-June, and the lakefront and 606 trail reopened about two weeks later, although the beaches remain closed, and visitors are required to “keep it moving” on the lakefront.

Now with the park of Lincoln Park near Montrose Beach also closed, Schneider’s family has a separate problem. They have a boat in Montrose Harbor, and for a time, they were cut off from getting there Sunday.

“Like the whole thing is a total nightmare and a pain,” Schneider said. “My family pays good money to be here. If they’re showing a valid pass to get in, let them in.”

Mick Montesi said he was nearby the mayor when the picture of the crowd on the grass was taken.

“She had her cameraman there they were taking photos of us and our crew,” he said.

He described this weekend’s scene as commonplace over the past two months, and added, “In person and in the flesh, it’s not as bad as that photo suggests.”

Montesi said the fence went up shortly after the crowded picture made the rounds on social media, but if the object is to keep people from crossing over, there was a hole in that plan – because there was a hole in the fence.

“I understand where her frustration is and concern is coming from,” Schneider said. But he added, “Where are people expected to go to when the beaches are closed it’s 95 degrees out?”

“You cannot stop people from wanting to spend time outside in the last 30 to 60 days of good weather that’s left. First you close the beaches – guess what, people move to the grassy areas,” Montesi said. “You’re not going to change people’s behavior. You’re just going to move them inland.”

The Chicago Park District said it installed the fencing to deter large gatherings like those seen on Saturday. It is unclear how long the fencing will be up.

A worker told our crew the hole in the fence will be repaired.