Federal agents and police in several drug-plagued cities say they often face dealers carrying U.S.-made semiautomatic machine pistols and rarely see the imported semiautomatic assault rifles banned by the Bush administration.

The ban, announced last week by drug czar William Bennett, temporarily blocks the importation of semiautomatic assault rifles such as the AK-47. It does not address the U.S.-made compact, high-powered semiautomatic machine pistols that local and federal authorities say are preferred by drug dealers.Bennett and President Bush said the ban - in effect pending a review of whether the military-type assault rifles are used for sporting purposes - is aimed at stemming bloodshed linked to drug trafficking.

Federal agents and police in New York, Washington, D.C., and elsewhere praised the ban as a "good first step" but said it does not address their primary problem.

Law enforcement officials cite the easily concealed machine pistols when asked what drug dealers carry. They say the bulky assault rifles do not lend themselves to the inner-city battlefields where much drug-related violence occurs.

"We are regularly facing weapons, but frankly, the biggest problem is semiautomatic machine pistols," said Robert Stutman, special agent in charge of the New York office of the federal Drug Enforcement Agency.

"That's the predominant weapon in D.C., New York, wherever," Bureau of Alcohol, Tobacco and Firearms spokesman Don Pedersen said of the semiautomatic machine pistols. "That's what everybody's afraid of, a lot of firepower."

The semiautomatic machine pistols - MAC-10s, MAC-11s and TEC-9s among scores of other U.S.-made varieties - are only slightly larger than a handgun. They can rapidly fire up to 30 large-caliber bullets as fast as the banned rifles but are more easily hidden, officials said.