HARRISBURG — The Pennsylvania attorney general’s office launched an effort Thursday to improve the use of firearms databases, so law enforcement can better track guns used in crimes and, ultimately, clamp down on gun violence.

The move comes amid a surge in such violence in Philadelphia. The city's rate of homicides this year is about the same as it was in 2018, when Philadelphia recorded 349 of them, the most since 2007.

Speaking at a news conference in Erie, Attorney General Josh Shapiro called gun violence a "public health epidemic."

To attack it, he wants police departments to enter serial numbers from every gun used in a crime or seized by police into a federal law-enforcement database, so its original seller can be identified and the information shared with other law enforcement agencies.

"Because this information is not shared, we actually have no idea how many crime guns were recovered in Pennsylvania last year, and that makes us all less safe," Shapiro said.

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives and criminologists say tracing the source of every gun used in a crime can provide leads to gun traffickers or illegal sellers and purchasers. But law enforcement analysts say that not every police department in the U.S. traces all such firearms.

Pennsylvania law requires guns used in crimes to be traced, and information can be submitted various ways to the ATF.

About 433 out of about 1,100 law enforcement agencies in Pennsylvania are using eTrace, an internet-based system that allows law enforcement agencies to submit traces to the federal agency, the attorney general's office said.

Of those, just 63 allow other police departments to see what they submit to the tracing system, the office said.

David Chipman, a retired ATF agent and now senior policy adviser for the Giffords Center, said Pennsylvania is following in the footsteps of New Jersey , when it became the first state to require police to trace every gun seized and to share that information with the state attorney general.

That should be a baseline requirement of police departments, Chipman said. But he acknowledged that some don't have the resources while others may simply not understand the value of sharing information.

"Being able to see the big picture of what everybody is seeing allows you to see the whole pie as opposed just to your compartmentalized slice," Chipman said.

Most guns used in crimes change hands multiple times, and a small number of firearms are used in a large number of crimes, Shapiro said.

Shapiro also said his office wants retailers to submit gun-sale records electronically to get rid of a police backlog of paper records that are waiting to be entered into a database.

That will allow law enforcement to more quickly trace guns used in crimes, Shapiro said.

One source of the guns is the theft of legal guns from homes and vehicles, and part of the initiative will be to emphasize safe gun storage, Shapiro's office said.

In the meantime, Shapiro said his office is helping assemble an investigative team to target illegal gun trafficking that includes federal agents, some county prosecutors, and the Philadelphia and Pittsburgh police departments.