Police are investigating whether David Gregory, the host of NBC's "Meet the Press," violated any city laws after he displayed what appeared to be a 30-round gun magazine Sunday on the show, a Washington Metropolitan Police Department spokesman told Politico.

Several pro-gun and conservative groups have been upset about Gregory showing a 30-round AR-15 magazine during an interview with National Rifle Association CEO Wayne LaPierre.

Those groups point to section 7-2506.01 of the District of Columbia Code, which states, "No person in the District shall possess, sell, or transfer any large capacity ammunition feeding device regardless of whether the device is attached to a firearm."

That device is defined as a "magazine, belt, drum, feed strip, or similar device that has a capacity of, or that can be readily restored or converted to accept, more than 10 rounds of ammunition."

"There are D.C. code violations, D.C. code restrictions on guns, ammunition. We are investigating this matter," Metropolitan Police spokesman Araz Alali told Politico. He did not elaborate on the investigation.

Pro-gun groups have also questioned CNN anchor Don Lemon after his comments about an AR-15 in Colorado.

Police have not said that either of the TV hosts are being investigated specifically, with the spokesman telling Politico that the investigation in D.C. is regarding "this whole entire incident."

On the program in which Gregory appeared to show the magazine, he asked LaPierre if he would concede that putting armed security in each school might not work "because there have been cases where armed guards have not prevented this kind of massacre."

On Friday, LaPierre asked Congress for money to put a police officer in every school and said at a press conference, "the only thing that stops a bad guy with a gun is a good guy with a gun."

"Look, a gun is a tool. The problem is the criminal," he told Gregory on "Meet the Press."

Last week, President Barack Obama called on Congress to take up and pass "common sense legislation that has the support of a majority of the American people."

Obama also tasked Vice President Joe Biden with leading the effort to come up with a comprehensive set of proposals to keep children safe. That would include addressing school safety, mental illness, and "a culture that too often glorifies guns and violence."

Biden helped draft the 1994 crime bill that led to the Federal Assault Weapons Ban that year, which expired a decade later. Previous efforts to renew the bill have failed. Obama said he wants the proposals by January and that he'll do "everything in my power as president to advance these efforts."

LaPierre told Gregory that not a single new gun regulation would make children safer, that "a media machine" relishes blaming the gun industry for each new attack like the one that occurred at a Connecticut elementary school, and that a White House task force on gun violence may try to undermine the Second Amendment.

LaPierre also has said the arming of every single school in America needs to come "before we engage in any lengthy debate over legislation, regulation or anything else," and also before children return to school.

The NRA leader dismissed efforts to revive the assault weapons ban as a "phony piece of legislation" that's built on lies. He made clear it was highly unlikely that the NRA could support any new gun regulations.

"If it's crazy to call for putting police and armed security in our schools to protect our children, then call me crazy," LaPierre said Sunday on NBC. "I think the American people think it's crazy not to do it. It's the one thing that would keep people safe."

Casey McNerthney can be reached at 206-448-8220 or at caseymcnerthney@seattlepi.com. Follow Casey on Twitter at twitter.com/mcnerthney.