CHICAGO >> During Memorial Day weekend, this city reopens its Lake Michigan beaches, regular fireworks displays start at Navy Pier and the downtown streets and spruced-up Riverwalk are crowded with tourists.

But the holiday weekend is often seen here as the start of heightened violence, as well. That has been particularly worrying this year to community leaders and city officials, as they grapple with a rise in gun violence that has traumatized some neighborhoods and left city officials searching for new ways to subdue street crime.

“If something doesn’t change, if we don’t get jobs for these kids, if we don’t change the economic situation, I’m worried that we could be looking at a bloodbath,” said the Rev. Corey Brooks, a pastor on the city’s South Side, a mostly African-American area where some of the shootings have been concentrated. “If something doesn’t happen, I fear that we’re potentially looking at one of the worst summers we’ve ever had.”

As of Friday morning, homicides in Chicago were up 52 percent in 2016, compared with the same period a year ago, and shootings had increased by 50 percent, though the pace of violence had slowed in recent weeks, police said. Only five months into the year, at least 233 people had been killed.

Officials are struggling with the problem, and are using a range of strategies as the murder rate in the nation’s third-largest city outpaces that of New York and Los Angeles.

Over the weekend, Chicago police increased the number of officers on the streets. About a week after a gang sweep that led to the arrests of 140 people, police said they planned to have extra foot patrols in parks and neighborhoods and more officers on bicycles. They are also using social media to track potentially troublesome house parties.

“I think you all know how important this weekend is,” police superintendent, Eddie Johnson, said Friday afternoon at a meeting with his top command staff.

On Friday evening, people gathered at more than 100 gymnasiums, parks and churches around the city to call for gang members and others to stop the violence that has long plagued some Chicago neighborhoods. The activities were the start of Mayor Rahm Emanuel’s third annual Summer of Faith and Action initiative, which promotes safety and urges people to put down their guns.

“If we all come together and reclaim our streets, reclaim our parks, there’s no room for the gangbangers,” Emanuel said, stopping by one of the gatherings on the Southwest Side on Friday night where people played basketball and painted murals.

“I would also say to the gangbangers what Eddie Johnson said,” Emanuel said, referring to his recently appointed police superintendent. “There’s a small percentage creating an overabundance of the gun violence. The police department knows who you are. They know where you live. And they know what you’re doing.”

For a few hours Friday evening, under periods of pounding rain, the peace held, and police scanners were filled with mundane reports of disturbances and crowd-control problems after a Beyoncé concert. But by Saturday evening, police reported that 19 people had been shot, four fatally, including a 15-year-old girl.

Last year during the three-day Memorial Day weekend, there were 46 shootings in Chicago, and 14 people were killed, police said. Other years have been quieter; in 2013, there were 22 shootings and six deaths.

The worries about summer come at an extraordinarily complicated time for Chicago, which is facing parallel crises: a drastic spike in violent crime, and a Police Department viewed with suspicion, even derision, in some neighborhoods.

Long-strained relations between Chicago police and residents, especially African-Americans, boiled over after the November release of dashboard camera video showing a white officer shooting a black teenager, Laquan McDonald, 16 times.

In the months afterward, Emanuel faced calls for his resignation, the city’s police superintendent was fired, and the Justice Department began an investigation into the police department’s practices. Last month, a task force appointed by Emanuel issued a scathing report that said racism had contributed to a long pattern of institutional failures by the department and that the department had lost the trust of residents.

That mistrust, some here say, has made it harder to solve crimes on the streets: Witnesses and victims often choose not to share information with police.

No one knows for sure why Chicago’s violence has increased this year, but police say it is largely the result of a small number of people involved with the city’s increasingly splintered set of gangs, and a rising number of disputes playing out on social media. A new area of concern is shootings along the expressways, where authorities say gang feuds are spilling out of the neighborhoods. There have been 20 shootings along Chicago-area expressways this year, police said, and no arrests.

“This has all amped up from what I’ve ever seen,” Pfleger said. “There’s a boiling point, and guns have become part of America’s wardrobe. People out here presume everyone has one, and they’ll tell you, ‘I’m going to draw mine before I get laid down.’”

Chicago’s population of 2.7 million is nearly equally split among whites, blacks and Hispanics, but most of the shootings have taken place in black and Hispanic neighborhoods on the city’s South and West Sides, and the majority of the victims have been African-American.

© 2016 The New York Times Company