One of the nation’s leading gun control groups has bought television time during Sunday’s Super Bowl in an effort to push Congress to pass universal background checks on all firearm purchases.

The 30-second spot by Mayors Against Illegal Guns will run on CBS stations in the Washington, D.C., market during the break coming out of halftime, officials at the group said Saturday. The officials declined to say exactly how much they had spent on the advertising, but said it was in the “six figures.”

The ad shows images of children as “America, the Beautiful” plays. One child notes that the National Rifle Association once supported broader background checks.

As the music keeps playing, the ad shows a clip of Wayne LaPierre, the chief executive of the N.R.A., saying in 1999 that the organization could support background checks.

“We think it’s reasonable to provide mandatory, instant criminal background checks for every sale at every gun show,” Mr. LaPierre says in the ad. “No loopholes anywhere, for anyone.”

The gun rights organization has since changed its position over the years. At a Congressional hearing this week, Mr. LaPierre said the N.R.A. did not support expanding the criminal background check system to private sales at gun shows and elsewhere. He said the current system was ineffective.

In the Super Bowl ad by the mayors group, another child says: “America can do this. For us. Please.” And it concludes with a screen that says: “Background checks for all gun purchases. It’s time.”

President Obama has joined with gun control organizations to push for stiffer firearms laws after the massacre that killed 20 children at an elementary school in Newtown, Conn., in December. One crucial measure would expand the background check system to cover sales of gun between private citizens.