GREENSBORO, N.C. (AP) _ Accusing the U.S. Food and Drug Administration of overstepping its authority, the tobacco industry Monday asked a judge to block marketing and sales regulations aimed at curbing teen-age smoking.

The new FDA rules begin taking effect Feb. 28 with a requirement that young people present a photo ID for proof of age before buying cigarettes. Future steps would restrict advertising in an effort to cut smoking by teen-agers.

Richard Cooper, an attorney for R.J. Reynolds Tobacco Co. and a former FDA counsel, told U.S. District Judge William Osteen the FDA is taking a first step toward banning tobacco.

``Before us today is an extraordinary exertion of power by a federal agency,'' he said. ``The FDA wants to exert its jurisdiction over the entire tobacco industry.''

But FDA Commissioner David Kessler said the new rules are needed for a severe problem.

``What's at stake is the future health of some of our children,'' he said after attending the five-hour hearing at the federal court in Greensboro, N.C. ``The president stands firmly behind the regulations to try in a common-sense way to reduce the number of children who will become addicted.''

Kessler, who has said he is stepping down from his post this month, declined further comment.

Osteen, a former tobacco lobbyist for North Carolina tobacco growers, heard arguments on a motion by four cigarette makers and an advertising firm to decide without a trial that the FDA lacks such authority.

Cooper noted that the FDA did not act on the Surgeon General's first warnings about the health effects of cigarettes in 1965.

``Why? Because FDA had no jurisdiction,'' Cooper said.

A U.S. Justice Department lawyer disagreed.

``If Congress wants to preempt the FDA from exerting jurisdiction, it can do so,'' George Phillips told Osteen. ``It has not done this.''

The FDA issued the regulations last year, saying it was acting in its capacity as a regulator of drugs.

According to President Clinton, the restrictions are needed to cut in half the 1 million teen-agers who start smoking each year.

Justice Department attorney Gerald Kell said the FDA classifies teen-age smoking as a pediatric disease and said that teen-agers, unlike adults, are too young to make a rational decision about whether to smoke.

Earlier, Cooper had argued that if the FDA was following its own policies, it would ban cigarettes outright after classifying them as ``unsafe and dangerous.''

Osteen questioned Congress' failure to act rather than leaving the issue to the FDA. ``Why doesn't Congress just ban smoking by minors instead of dancing around the perimeter?'' he said.

Kell said the tobacco industry is fighting so hard because it doesn't advertise precisely what cigarettes are intended for _ to satisfy the urge for nicotine.

After hearing arguments about FDA's jurisdictional authority in the morning, Osteen heard from lawyers on the First Amendment issues raised by the plaintiffs.

Attorney Daniel Troy, arguing for the plaintiffs, said the FDA was going too far.

``These are broad, comprehensive restrictions that are patently over-broad and unprecedented,'' he said, adding that the restrictions would prevent tobacco companies from advertising in such magazines as ``Better Homes and Gardens.''

``Time and time again, the FDA has thrown up its hands and said, `It's too hard to draw a line,' and put up blanket restrictions,'' he said.

That prompted Osteen to say: ``You can't really have precision.''

Outside the court, John Fithian of the Freedom to Advertise Coalition said the case is far broader than tobacco advertising.

``It will affect how we advertise products in the future,'' he said. ``It's legal and reasonable to protect children. The problem with these regulations is that they are overly broad and affect every form of media.''

Osteen said a ruling is at least five weeks away. ``This case is too serious for both sides to give it any less consideration,'' he said.

The plaintiffs in the case are Brown & Williamson Tobacco Corp., Lorillard Tobacco Co., Philip Morris Inc., R.J. Reynolds Tobacco Co. and Coyne Beahm Inc., a North Carolina advertising firm.

Liggett Group Inc. was a plaintiff when the lawsuit was filed but later withdrew from the case.