The nation's top anti-drug official said people need to overcome their "reefer blindness" and see that illicit marijuana gardens are a terrorist threat to the public's health and safety, as well as to the environment.

John P. Walters, President Bush's drug czar, said the people who plant and tend the gardens are terrorists who wouldn't hesitate to help other terrorists get into the country with the aim of causing mass casualties. Walters made the comments at a Thursday press conference that provided an update on the "Operation Alesia" marijuana-eradication effort.

"Don't buy drugs. They fund violence and terror," he said.

After touring gardens raided this week in Shasta County, Walters said the officers who are destroying the gardens are performing hard, dangerous work in rough terrain. He said growers have been known to have weapons, including assault rifles.

"These people are armed; they're dangerous," he said. He called them "violent criminal terrorists."

Walters, whose official title is director of the White House Office of National Drug Control Policy, said too many people write off marijuana as harmless. "We have kind of a 'reefer blindness,' " he said.

No arrests have been made so far in the four days of raids, the opening leg of what Shasta County Sheriff Tom Bosenko has promised will be at least two straight weeks of daily raids.

He said suspects have been hard to find because their familiarity with their terrain makes it easy for them to flee quickly.

Although crews doing the raids are using Black Hawk and other helicopters to drop in on some of the gardens, Bosenko said they don't want to give the growers any warning of a raid.

"We try to move in under stealth," he said.