By MICHAEL RUBINKAM | Associated Press

America's most powerful pro-gun group is using a new Pennsylvania state law that allows them to challenge local gun control measures, filing lawsuits against ordinances in three cities, including requirements that owners report lost or stolen firearms.

The cities said they will fight the National Rifle Association, contending the measures are a sensible way to address deadly gun violence.

“This should be a wake-up call for citizens across Pennsylvania,” Pittsburgh Mayor Bill Peduto said. “We're not taking away anyone's right to own a gun, or 10 or 20 guns. What we're saying is when a gun is lost or stolen, you've got to report it. Too many people are being killed in the streets of Pittsburgh and other cities with stolen guns.”

The lawsuits add a new dimension to America's divisive debates over gun control. Advocates of tougher gun control legislation point to a string of mass shootings around the country and gun-related crime in urban areas. Gun rights activists worry stricter laws are a pathway to encroaching on the right to bear arms enshrined in the Second Amendment of the U.S. Constitution.    

The controversy in Pennsylvania, which has a strong tradition of hunting and gun ownership, centers on a 40-year-old state law prohibiting municipalities from approving ordinances that regulate the ownership, possession, transfer or transportation of guns or ammunition. Scores of cities and towns ignored the prohibition, and gun rights groups said the local measures were difficult to challenge because judges have ruled that plaintiffs could not prove harm.

Under a state law that took effect last week, gun owners no longer have to show they have been harmed by an ordinance to win in court.

Armed with the law, the NRA filed lawsuits Wednesday against ordinances in Philadelphia, Pittsburgh and Lancaster.

The three cities have “openly defied” the state law that forbids municipalities from regulating firearms, said Chris Cox, executive director of the NRA's Institute for Legislative Action.

The NRA suit filed against Philadelphia targets seven ordinances, including ones that require owners to report lost or stolen firearms; prohibit guns from city-owned facilities; and ban weapons possession by people subject to protection-from-abuse orders or who are found to pose a risk of “imminent harm” to themselves or others.

Philadelphia officials have long said the measures are needed to combat gun violence that claims hundreds of lives each year.

In the small city of Lancaster, the NRA is challenging an ordinance that requires gun owners to tell police when a firearm is lost or stolen.

Lancaster Mayor Rick Gray denounced the NRA lawsuit as “pathetic” and said the city's attorney had determined its ordinance could withstand legal scrutiny.

Philadelphia, Pittsburgh and Lancaster are fighting the new state law in court, arguing lawmakers didn't follow constitutional procedure for passing legislation.

Under threat of litigation from several smaller gun rights groups, more than 20 Pennsylvania municipalities already have moved to repeal their firearms ordinances instead of defending them in court. Another group, Houston-based U.S. Law Shield, sued the capital of Harrisburg on Tuesday over its gun laws.