HARRISBURG - Gov. Ed Rendell and other Pennsylvania officials angered by the shooting deaths of three Pittsburgh police officers made an emotional plea to Congress on Wednesday to ban assault weapons like the one they say was carried by the suspect.

Rendell, Pittsburgh Mayor Luke Ravenstahl and nearly a dozen other mayors and public safety officials from around the state stood next to a table full of assault weapons to make their case for reinstating a ban that expired five years ago.

"Time and time again, in Pennsylvania and across the length and breadth of our great country, our police are finding themselves outgunned," Rendell told reporters.

Rendell, who fought crime as Philadelphia's district attorney and mayor, reeled off a list of government statistics that he said underscored the effectiveness of the assault weapons ban.

"People who say these laws don't matter, they're dead wrong," he said.

In 1994, Congress approved a 10-year federal ban on the sale of assault weapons and let it expire in 2004. Prospects for a re-enactment are not bright.

Last month, 65 House Democrats including five from Pennsylvania wrote to U.S. Attorney General Eric Holder to say they would oppose re-enacting the law. Such heavy Democratic opposition probably would doom any legislative drive.

In their letter, the representatives said people use the guns for sport and hunting assertions disputed by Rendell and the police officials as well as for home defense, and that a ban on the weapons does not bring down crime rates.

Authorities say Richard Poplawski was armed with an AK-47 assault rifle and other weapons when he gunned down three Pittsburgh officers earlier this month.

Officers Eric Kelly, Stephen Mayhle and Paul Sciullo arrived at Poplawski's home early on April 4 after Poplawski's mother called 911 to report that they were arguing and that she wanted officers to kick him out of the house.

On Wednesday morning, Poplawski, 22, appeared at a brief hearing in Pittsburgh City Court to waive a preliminary hearing at which he could have challenged the evidence against him before the matter goes to trial.

A county judge has ordered police, attorneys and witnesses not to discuss details of the alleged crimes, and Poplawski's public defender, Lisa Middleman, would not say why she chose to waive the hearing.

Poplawski was scheduled for a formal arraignment on June 1.

Ravenstahl and Pittsburgh Police Chief Nate Harper Jr. expressed disbelief that the officers' deaths would not change opposition to new gun-control measures.

"How much blood has to be spilled on the streets of America?" Harper questioned.

"If the events of the last Saturday in Pittsburgh don't change your mind, I don't know what will," Ravenstahl said.