Updated

Amid the tidal wave of shock and grief that followed the mass murder at Sandy Hook Elementary School in Newtown, Conn., the gun-control lobby immediately launched a well-coordinated campaign to pressure Congress and the Obama administration into enacting stricter regulation of guns and rifles.

These forces -- led by New York Mayor Michael Bloomberg, Rep. Carolyn McCarthy, D-N.Y., and Sen. Dianne Feinstein, D-Calif. -- had the playing field largely to themselves.

That is soon to change.

A statement released late Tuesday by the Fairfax, Va.-based organization announced that it would hold a "major" news conference on Friday. Issued by an aide to NRA President Wayne LaPierre, the statement also conveyed condolences for the murders and expressed the group's willingness to offer "meaningful contributions to help make sure this never happens again."

"The National Rifle Association of America is made up of four million moms and dads, sons and daughters -- and we were shocked, saddened and heartbroken by the news of the horrific and senseless murders in Newtown," the statement said.

More On This...

"Out of respect for the families, and as a matter of common decency, we have given time for mourning, prayer and a full investigation of the facts before commenting."

Sources close to the issue had earlier alerted Fox News that the National Rifle Association -- which has remained silent since Newtown, chiefly to allow for a proper period for mourning -- would soon start to "push back" against the gun-control lobby.

"If we're going to have a conversation, then let's have a comprehensive conversation," said one industry source.  "If we're going to talk about the Second Amendment, then let's also talk about the First Amendment, and Hollywood, and the video games that teach young kids how to shoot heads.

"If you really want to stop incidents like this," the source continued, "passing one more law is not going to do a damn thing. Columbine happened when? In 1999. Smack in the middle of the original assault-weapons ban."

Indications that the NRA would soon end its period of self-imposed post-Newtown silence came after Feinstein announced her plan to introduce an updated version of the assault-weapons ban that she steered to passage in 1994, and which expired a decade later.

"I have been working with my staff for over a year on this legislation," Feinstein said in a statement issued Monday. "It will be carefully focused on the most dangerous guns ... while protecting the rights of gun owners."

Feinstein said her legislation will outlaw the sale, import and manufacture of more than 100 different firearms, including "semiautomatic rifles, handguns and shotguns that can accept a detachable magazine and semiautomatic rifles and handguns with a fixed magazine that can accept more than ten rounds."

The measure would also ban the sale, import and manufacture of "large-capacity ammunition feeding devices (magazines, strips and drums) capable of accepting more than ten rounds."

To protect legal gun owners, the Feinstein measure would "grandfather in" those weapons legally owned at the time the measure would become law. It would also exempt antiques, manually operated weapons, permanently disabled weapons, and more than 900 specifically named firearms commonly used for hunting and sporting.

Industry sources acknowledged that public sentiment after Newtown is unlike that which followed similar attacks over the past decade, because of the presence of so many children among the victims -- and that the NRA will likely face a tougher climate in which to try to forestall the enactment of tighter gun control measures.

But they also indicated that Feinstein's provisions relating to the number of rounds a weapon can accommodate will be contested fiercely. "A standard semi-automatic handgun holds 12 to 14 rounds," one source close to the issue told Fox News. "Everyone would have to retool and new hardware would have to be made. That's going to be very expensive to manufacturers."