WASHINGTON (AP) _ Attorney General Janet Reno and FBI Director Louis J. Freeh say U.S. cities and towns remain vulnerable to chemical and biological terrorism despite recent efforts to improve protections.

``We need to make sure we have a significant stockpile _ and I don't think we do _ of vaccines and other medications,'' Reno said Wednesday before a joint hearing of the Senate Intelligence Committee and Judiciary subcommittee on technology and terrorism. The panels have been holding a series of hearings on terrorism.

Freeh testified that local police lack adequate equipment for dealing with such attacks, calling that ``the greatest vulnerability that we have right now.''

The February anthrax scare in Las Vegas served as a ``dress rehearsal'' that taught some important lessons, he said.

Two men were arrested Feb. 18 on suspicion of having deadly weapons-grade anthrax. The charges were dropped five days later when the material was found to be a veterinary vaccine.

Freeh said it should not have taken the FBI 30 hours to determine the material posed no threat. ``That's a long time to wait for an answer,'' said Freeh. He said the FBI is trying to develop ways to speed the process.

Sen. Carl Levin, D-Mich., said classified administration testimony earlier this week suggested a ``high degree of likelihood that such an attack would occur in 10 years.''

Neither Reno nor Freeh would provide publicly their estimate of the probability of such an attack, but Freeh said, ``It's an issue that requires a lot of attention.''

Sen. John Kyl, R-Ariz., who presided over the hearing, said the classified briefing the committee received ``painted a sobering picture of growing proliferation networks, aggressive national chemical-biological-weapons development programs and increasing levels of violence and lethality associated with terrorism.''