City officials announced Wednesday they would dust off and enforce a decade-old ordinance designed to assure that lost or stolen guns are properly reported.

Philadelphia District Attorney Larry Krasner said at a morning news conference that the city’s Failure to Report Lost or Stolen Firearm code has been underused by gun owners. The code dictates heavy fines and possible jail time for any gun owner who does not tell authorities when a firearm is lost or stolen.

Krasner said many guns claimed to be lost or stolen never were. "They were sold illegally, and they end up in the hands of people who commit crimes,” he said.

Enforcing the old measure would help prevent such illegal trafficking in weapons, track the distribution of firearms through city streets and help keep guns from violent offenders and children, city officials said.

The city is establishing a 30-day amnesty period for people who have not reported guns lost or stolen to do so.

Krasner said the goal of the initiative is to “enforce City Council’s ordinance, which is designed to hold accountable irresponsible individuals who fail to report lost or stolen firearms.”

“It’s pretty easy. Somebody steals your gun, or you lose your gun, get on the phone and call 911 to let them know that happened. That’s it.”

He said the ordinance “is not something that regulates guns. It doesn’t even regulate gun owners. It’s something that regulates people who say they have lost their guns, or who say their guns were stolen.”

The district attorney’s Gun Violence Task Force will seek to trace guns to the last owner. “If we determine someone was involved in a straw purchasing case, and we can prosecute it, we will," Krasner said. "If no illegal transfer occurred, then we will conclude the investigation.”

Many illegal gun purchases, Police Commissioner Richard Ross said, are by people looking to avoid the criminal background check required in legal sales.

The 2009 city ordinance was challenged in a 2015 lawsuit by the National Rifle Association, arguing it violated gun owners' civil rights. Appellate courts ruled that a state law allowing “membership organizations” to challenge local gun laws was unconstitutional. But the city code has not been enforced.

Krasner dismantled a program called GunStat, initiated in 2012 by District Attorney Seth Williams to reduce gun violence in certain crime hot spots and later expanded. Under GunStat, prosecutors sought state prison sentences for defendants in gun-possession cases, tracked offenders, and shared intelligence with other city agencies.