by KYW's Mike Dunn

Philadelphia mayor Michael Nutter says the National Rifle Association -- which has sued to stop the city from enacting its own gun laws -- owes the Liczbinski family an apology.

Last month the mayor quickly signed five new gun restrictions into law, and just as quickly the NRA filed a lawsuit in court to stop enforcement of the new legislation. A temporary restraining order was issued and a hearing scheduled for May 19th.

One of those bills would have outlawed the sale and use of assault weapons, including the type used on Saturday in the murder of Sgt. Stephen Liczbinski.

On Monday morning Mayor Nutter (in file photo above) said the officer's death shows, in his view, that there is no legitimate sports use for this type of weapon. And he had this message for the NRA:

"I think that they should make an immediate statement acknowledging that there is no legitimate reason for anyone to have such a weapon and should join us in supporting -- at least -- this kind of reasonable legislation. They don't have a leg to stand on, and they owe the Liczbinski family an apology for their obstructionist activity in this regard."

The NRA contends that only the state, not the city, can enact gun laws. 

The president of the NRA, John Sigler, responding on Monday afternoon by saying the mayor "should be ashamed of himself" for, in his view, politicizing the officer's death:

"I actually think that Mayor Nutter owes all the police officers of the City of Philadelphia -- for that matter, all the police officers throughout the United States -- a very, very large apology for using this tragic event as an opportunity to engage in his own political rhetoric."

Sigler, a former police officer in Dover, Del., reiterated the NRA's belief that the city-specific gun laws signed by Nutter are not legal.

Nutter also called on the remaining at-large suspect, Eric Floyd, to give himself up immediately. In Nutter's words, "It is time to face the music for what you have done."