The Senate reaffirmed its vote to impose a partial ban on semiautomatic assault weapons yesterday as it neared approval of an omnibus anti-crime bill that authorizes the death penalty for more than 30 federal crimes and seeks to limit death row appeals.

Before adjourning early today for its July 4 recess, the Senate added the death penalty for drug "kingpins", refused to impose it for murder in connection with certain civil rights violations and approved an expansion of federal crime-fighting efforts, including hiring of nearly 3,000 new agents and prosecutors.

Voting 25 to 73, the Senate rejected a proposal to substitute mandatory life imprisonment without parole for all death penalty provisions.

Final approval was postponed until July 11 when the Senate will consider a bipartisan proposal to strengthen prosecution of savings-and-loan fraud.

Despite a month-long effort by the National Rifle Association to persuade senators to reverse themselves and kill the assault weapons ban, the Senate voted 50 to 48 in its favor, essentially the same narrow margin by which the proposal was approved in two successive votes May 23.

With Vice President Quayle presiding and ready to vote in case of a tie, the tally seemed in doubt to the last minute as both sides took turns lobbying Sen. Alfonse M. D'Amato (R-N.Y.), who voted for the ban last month but had come under heavy pressure from the NRA and its Senate supporters to switch.

As senators watched anxiously, D'Amato finally cast his vote again for the ban.

If he had switched sides, the result would have been a 49-to-49 tie, enabling Quayle to cast the deciding vote to drop the proposal, which goes well beyond an import ban on assault weapons that was imposed by President Bush last July.

The Senate ban, sponsored by Sen. Dennis DeConcini (D-Ariz.), a former NRA favorite who became outraged at use of assault weapons in drug-related violent crime, would prohibit the manufacture, distribution and sale of nine types of assault weapons that officials have said are most often used in such crimes.

The proscribed weapons would include four categories of U.S.-made guns not covered by Bush's import ban as well as five types of foreign-made weapons that were included in his order, including the AK-47 used in the Stockton, Calif., schoolyard massacre two years ago and more recent drive-by shootings in other cities.

As before, all Washington-area senators voted for the ban.

A broader ban is pending in the House, but the final outcome for the legislation is unclear.

The crime bill includes most of President Bush's major anti-crime proposals, some in modified form. As requested, it would reinstate and broaden the death penalty, primarily for murder, espionage and treason.

It would also limit the number and duration of appeals by prisoners on death row, although not as much as Bush wanted.

A Democratic-backed reorganization of the Justice Department was dropped, along with an administration proposal to allow courts to consider evidence seized without warrants.

Amendments approved last night would expand federal efforts to curb child abuse, impose new penalties for child pornography, expand victims' rights in criminal proceedings, create new penalties in trafficking in "ice" (a highly addictive form of methamphetamine), impose stringent new work rules for federal prisoners, require a 30-year minimum sentence for child kidnapping and exempt Indian tribes from death penalty provisions unless the tribe agrees.