RICHMOND, FEB. 2 -- The Virginia House today overwhelmingly passed a bill that would require criminal background checks on purchasers of virtually all firearms, vastly expanding state law regulating gun purchases.

Both gun control supporters and opponents rallied around the measure, which extends a law Virginia passed two years ago requiring background checks only on buyers of some types of handguns. Those convicted of many types of violent crimes already are barred from purchasing weapons under state and federal laws.

Although there was broad consensus on the bill -- House Speaker A.L. Philpott (D-Henry), an ardent gun control foe, cast the only dissenting vote -- the debate on most other gun measures before the General Assembly this year is growing more acrimonious by the day.

The National Rifle Association has paid for radio ads that attempt to stir opposition to a bill that would require a three-day waiting period on handgun purchases by taking a broad swipe at Northern Virginians.

"Our great Senator Harry F. Byrd used to tell politicians the real Virginia starts at Fredericksburg, because it seems up north the people behave less like real Virginians," reads a transcript of the radio ad, which is being broadcast on downstate stations.

"Well, if you need proof, this is it. Some Northern Virginia anti-gun politicians decided just days ago that you need anti-gun laws like they have in Washington, D.C., and New York City -- the same kind of harassment schemes we all know have been an embarrassing and tragic failure."

Actually, the bill the NRA objects to is sponsored by Del. Jean W. Cunningham, a Richmond Democrat.

"Truth is not an impediment to the NRA," said Sen. Moody E. Stallings Jr. (D-Virginia Beach), a gun control proponent.

Chuck Cunningham, the NRA's Richmond lobbyist, declined to comment on the radio ads. The waiting-period bill passed the Courts of Justice Committee tonight on a 10 to 9 vote, with one abstention. It now moves to the full House for a vote.

Gun control advocates want the issue of a three-day waiting period put before voters this fall in a referendum.

In the Capitol lobbying for the measure today was Sarah Brady, the wife of former White House press secretary James Brady, who was wounded during the attempted assassination of President Reagan in 1981.

While lauding the criminal background checks, Sarah Brady said a waiting period is needed to allow people to "cool off" if they are buying handguns to commit suicide or shoot someone in a "crime of passion."

"Thousands of these lives could be saved each year if handguns were not so accessible," she said. "It takes about as long to buy a gun as it does a quart of milk in this state."

Earlier this session, House leaders said there had been broad support among Democrats to put the waiting-period question before voters. After a barrage of advertising by the NRA and other groups, however, many rural Democrats are abandoning the coalition, the leaders said.

The NRA's Cunningham said the background check bill, which sailed through the House today and is expected to pass the Senate, makes a three-day waiting period unnecessary and unfair.

Criminal background checks are made through a computer network that allows dealers to approve or reject gun sales instantly, Cunningham argued, while the other measure amounts to a "three-day harassment period."