Judge Jack B. Weinstein said the new law shielding gun companies from lawsuits by cities and crime victims did not apply to New York's case against several major gun manufacturers. In a victory for gun makers, however, he found that the federal law is constitutional.

The legislation, which was championed by the National Rifle Association and signed into law by President Bush in October, barred lawsuits against gun makers or sellers, except for suits that alleged they had knowingly violated a law regarding the sale or marketing of firearms.

The city's case, which claims that gun suppliers violated public nuisance law by negligently and recklessly marketing its weapons, fell within that exception, Weinstein ruled.

The judge immediately stayed all action in the trial in order to allow gun manufacturers to appeal the decision.

New York had sued several of the main suppliers of handguns in the United States, arguing that gunmakers had created a public nuisance by fostering a situation that allowed widespread access to illegal firearms.

Similar suits had been filed by cities and states across the country.

In ruling that the federal law is constitutional, Weinstein said it "adequately balances congressional concern over the viability of the handgun industry and the concern of the states and municipalities for the safety of their populations against handgun violence spawned by careless merchandising."