As the Bush administration urged law enforcement officers and civilians to “be on the highest alert” in the aftermathof the F.B.I. warning of an imminent attack against the US, federal law enforcement agents raided medical marijuanaproviders across California yesterday. Federal agents raided at least three clubs, in San Francisco, Oakland andPetaluma. According to the San Francisco Independent Media Center, they raided five other sites as well. The Oaklandhome of long-time cannabis activist Ed Rosenthal, and the Sixth Street Harm Reduction Center in San Francisco, amedical marijuana club, were among the first raids by Drug Enforcement Agency officials. Four were arrested at thecenter. They face between 40 years to life in prison. The Harm Reduction Center serves about 200 patients a day, allwith doctors’ recommendations to get the drug. Many suffer chronic pain from AIDS and cancer.