A new nationwide advertising campaign by the National Rifle Association has drawn fire from police, the Department of Justice and rape victims' advocacy groups, who say the ads are misleading, sensational and dangerous.

"SHOULD YOU SHOOT A RAPIST BEFORE HE CUTS YOUR THROAT?" is the headline above a close-up photo of a hooded criminal. "It's up to you," begins the written message.

The tone and wording contrast with the previous "I'm the NRA" ad campaign, which emphasized the all-American backgrounds of the group's 3 million members. The NRA, founded in 1871 to "promote and encourage rifle shooting on a scientific basis," opposes nearly all government restrictions on ownership of guns, including handguns and machine guns.

"We in law enforcement are extremely distressed about the whole series of ads by the NRA," said Jerald R. Vaughn, executive director of the International Association of Chiefs of Police. "We see them as a very reckless and very dangerous call to arms that would be very destructive to public safety."

Vaughn, a former police officer in Denver and police chief in Garden City, Kan., and Largo, Fla., said the ads would hamper law enforcement by encouraging a "Wild West, everybody buy a gun and let's shoot it out" mentality.

The latest ad is one in a series of six full-page NRA promotions published beginning last month in The Washington Post, The New York Times, the Los Angeles Times, USA Today and other large newspapers.

"This is a particularly offensive ad," agreed Marcia Niemann, executive director of the National Coalition Against Domestic Violence. "It says to a woman: If you choose not to carry a gun, it's your own fault if you get raped."

The ad claims that "the Department of Justice found that only 3 percent of rape attempts are completed against armed victims."

But statisticians at the Justice Department say the statistic is misleading, particularly when cited out of context as in the NRA ad.

"It was a surprise to us," said Michael Rand, a statistician in the Department of Justice. "When we first saw the ad, it took us a whole day to find out where it came from."

The source turned out to be a report titled "Rape Victimization in 26 American Cities," published by the Justice Department in 1979. The report was based on surveys conducted in 1973-75 in the five then-largest U.S. cities -- New York, Chicago, Los Angeles, Philadelphia and Detroit -- and 21 others, including Washington, D.C.

But the total sample of rapes on which the 3 percent figure is based was "less than 50," Rand said. That is fewer than two rapes per city surveyed.

"It's not a reliable statistic," he said.

A spokesman for the NRA, Dave Warner, said the ad campaign was directed at "people in the middle who are neither anti-gun nor pro-gun." He denied that the ad encouraged people to buy guns.

"It did just what the designers of the ad wanted," Warner said, referring to the provocative headline and the photograph of a hooded attacker. "It got you to read the whole thing."

"The ad's message," he said, "is, 'Don't own a firearm if you don't want one, but don't let anyone deny you the right to own one if you want.' That's all the NRA has ever said, but this is the most effective way they've said it."

But representatives of advocacy groups for victims of rape and domestic violence, as well as the police-chiefs association's Vaughn, said the NRA ad used scare tactics to exploit women's fear of crime.

"We're not playing on fear," said NRA's Warner. "We're showing reality. This is stuff that's in your paper every day -- people getting shot or mugged or raped or whatever. Crime is a fact of life in this country."

About 46,000 rapes and 84,000 attempted rapes were reported in the U.S. last year, according to the Justice Department. How many of the victims were armed is not known, statistician Rand said.

The new ad campaign highlights a growing split between the NRA and the association of police chiefs, Vaughn said. The two groups were close allies until the late 1970s. But Vaughn said police chiefs are "shocked" by the increasingly "extreme" NRA positions in opposition to bans on the sale of machine guns, waiting periods for handgun sales and legislation outlawing "plastic guns" and firearms that don't meet minimum standards of detectability.What law enforcement officials object to most strenuously in the ad, Vaughn said, is "this myth that the NRA insists on perpetuating -- that if you buy a gun you'll be safe."

Even armed police officers, who tend to be in good physical shape and well-trained in firearm use, are vulnerable in violent situations, he pointed out. Fifteen U.S. police officers were killed last year by assailants who seized the officers' guns and opened fire.

"The police are not an antigun group," Vaughn said. "We carry guns as tools of our trade. But we are also aware of the tragedy that occurs day in, day out, as a result of easy access to handguns in this country."

"To say to a woman, 'You're safer if you carry a gun,' is extremely misleading," said Niemann of the National Coalition Against Domestic Violence. "When there are guns in the house -- whether owned by a man or a woman -- life is less safe for women. When those already prone to violence have access to a weapon, the chances of serious injury and death are even greater."

"If someone took the information in the ad literally," said Marjolijn Bijlefeld, associate director of the National Coalition to Ban Handguns, "it could cost them their life."

The implication that carrying a handgun will protect a woman against rape, she said, is "just not true."

Of the more than 9,000 handgun homicides reported to the FBI last year, Bijlefeld said, only 193 were justifiable homicides by civilians defending themselves. Of those, only 16 involved self-defensive shootings by women, four of whom shot their husbands to death.

She said the ad also misleadingly implies that rape is a crime that occurs between strangers, when more than half of all rapes are committed in domestic situations or by attackers who are acquainted with the victim.

The headline and picture in the NRA ad "terrorize women," said Marjorie Lewis, a co-founder of Rape Victim Companions, an advocacy group assisting rape victims in the Winchester, Va., area. "There are ways we can defend ourselves without carrying a concealed weapon."

Safer and more effective ways of resisting rape, she said, include use of physical force, scratching, biting, knee kicks to the groin, screaming, making a lot of noise and even throwing up.

Of the more than 50 rape victims that Lewis has worked with over the past decade, only three were raped by a man totally unknown to them.

"Sometimes a weapon gives you a false sense of security," said Elisa Rivetti, assistant to the director of the Rape Crisis Center in the District. The center advises women under attack to try to flee -- and if that fails, to "use their own bodies and natural reflexes, including well-aimed punches."

A spokesman for the District Police Department declined to comment specifically on the NRA ad, adding that it's "the policy of this department not to make recommendations concerning women arming themselves with guns."

District law prohibits the purchase of handguns but not rifles or shotguns, he said.

The decision to own a rifle or shotgun, the spokesman said, "is a personal one that can only be made by the individual involved. There always exists the possibility that they could be disarmed and the weapon used against them."