D.C. Police Chief Cathy L. Lanier listens to Montgomery County Police Chief J. Thomas Manger speak during a news conference following a meeting of the Major Cities Chiefs Association. (Matt McClain/The Washington Post)

Law enforcement officials from the Washington area and across the country said Monday that there has been a recent increase in shootings in several major cities but that they haven’t pinpointed what’s causing the spike in violence.

Officials from several cities, including the District, St. Louis, Chicago and Baltimore, met at the Newseum in the District to discuss the trend and possible solutions to the violence. They were joined by criminology professors, attorneys and others.

“We had this meeting as an urgent summit because we felt a sense of urgency because people are dying,” D.C. Police Chief Cathy L. Lanier said at a news conference after the summit. “We have not seen what we’re seeing right now in decades.”

The event was hosted by the Major Cities Chiefs Association (MCCA), which said a survey of its members showed that police in many cities are seeing more guns on the streets and more killings. Four of the nation’s largest cities — New York, Chicago, Houston and Philadelphia — recorded a rise in homicides by mid-
July compared with the same period in 2014.

The District has experienced the same trend. The city’s homicide toll for 2015 is now 87; the total for all of 2014 was 105. Violent crime in general also is on the increase compared with last year, police said.

The summit was organized by Lanier, Chicago Police Superintendent Garry McCarthy and MCCA President J. Thomas Manger, the police chief in Montgomery County, Md., following a conference call in late July, Darrel Stephens, executive director of MCCA, said in an e-mail.

During the summit, the group identified several issues prevalent across many of the major cities, with the proliferation of guns high among them.

Manger said at the conference that 40 percent of the 35 cities surveyed reported shooting scenes with multiple firearms, with an increased number of shell casings found at the scenes.

Among the recommendations that came out of the summit, the chiefs called for more stringent gun laws, including harsher penalties for gun crimes and the use of high-capacity magazines.

“We’re going to shooting scenes now where you’ve got more and more victims being shot, you’ve got more spent rounds being collected as evidence and we’re finding more and more high-capacity magazines involved in these shootings,” Manger said.

The District experienced this type of incident over the Fourth of July, when 52 bullet casings were recovered after a shootout that left one person dead and four others wounded.

In Chicago, which has the highest number of slayings of those surveyed by the MCCA with 235, the police department has seized over 3,400 illegal firearms this year, but the shootings continue. McCarthy has recently spoken out in favor of harsher sentences for people charged with gun-related offenses.

“Just think about that, if we’re taking three guns for every one that Los Angeles takes, and seven for every one that New York City takes, and now we’ve got a 22 percent increase in the number of gun arrests we’re making, something is going on,” McCarthy said in an interview.

Other trends identified include gang-related activity and retaliatory violence, which half the cities reported seeing an increase in. Also, 30 percent of responders said they think the use of synthetic drugs is contributing to the violence and reported that they have encountered offenders who were under the influence of the drugs.

The chiefs also recommended improving community partnerships, addressing the spread of synthetic drug use and having the Justice Department track and report crime statistics for the major cities monthly so that other chiefs can better follow the national trends.

One of the hardest-hit cities has been Baltimore. This summer, the city has seen an unprecedented number of killings, with more than 40 people slain both in May and June, a first for the city, according to the Baltimore Sun. The interim police commissioner, Kevin Davis, is trying to use federal agents to help investigate the city’s many homicide cases. Davis attended the summit but was not at the news conference.

“So we can’t be looking too far down the road because we’re in a moment we need to fight our way out of,” Davis told the Sun on Sunday. “Having [federal agents] embed with our homicide detectives and literally be on the streets of Baltimore, boots on the ground, is what we need right now.”

While Manger said police departments have been working hard, they haven’t been able to find a clear solution.

“If we had a strategy that was working, you know, we probably wouldn’t have had to have this summit,” he said. “If there was an easy answer, believe me, that’s the first thing I would have talked about.”

Peter Hermann contributed to this report.