A national gun control group began airing an advertisement on two Washington radio stations yesterday criticizing Rep. Robert L. Ehrlich Jr. for his record on handguns.

The ad -- scheduled to run eight times between yesterday and Tuesday -- is the first on radio or television in Maryland's 2002 gubernatorial campaign. The congressman from Baltimore County is the leading Republican candidate for governor.

"We targeted Ehrlich first because we have concerns about his record," said Amy Stilwell, a spokeswoman for the Brady Campaign to Prevent Gun Violence. "We feel strongly enough about it that we want to begin educating voters now."

Stilwell said the group spent $20,000 to $25,000 to purchase the eight 60-second ads on WTOP and WMAL. It plans to spend as much as $250,000 by the end of Maryland's campaign. The organization, formerly known as Handgun Control Inc., has not yet made a formal endorsement for governor.

The ad -- spoken by former congressman Michael D. Barnes, president of the Brady Campaign -- describes Ehrlich's record as "extremist" and says he "has always sided with the extreme gun lobby." Barnes says Ehrlich led the "gun lobby's fight against banning Saturday Night Special handguns" when he was a state delegate, and notes that he voted in Congress to overturn the federal ban on assault weapons.

A spokesman for Ehrlich said the ad inaccurately characterizes the congressman's record and turns the campaign negative before the summer has begun. "We are disappointed that the very first ad of this campaign season in Maryland is a personal attack on Bob," said spokesman Paul E. Schurick.

"Bob's long voting record on guns is mixed by any reasonable measure," Schurick said. "He's cast thousands of votes. They've decided to go in there and identify two out of a thousand and distort his record."

Ehrlich has voted in favor of such gun control measures as trigger locks and background checks for would-be gun purchasers.

Both Ehrlich and the Brady Campaign back a program known as Project Exile -- requiring tough mandatory sentences for felons caught with guns -- but Stilwell said that's not enough. "You need to take preventive measures, too," she said.

A state handgun control group -- Marylanders Against Handgun Abuse -- also has begun a campaign to highlight Ehrlich's record on guns. The two gun control groups say they're independent of the campaign of Ehrlich's leading Democratic opponent, Lt. Gov. Kathleen Kennedy Townsend.