VANCOUVER -- Riding high after U.S. states rejected measures to relax drug laws, drug czar John Walters came to Canada this week to talk tough about a new front in the drug war.

Marijuana poses a greater danger to the United States than heroin, cocaine or amphetamines, said Mr. Walters, the director of the White House Office of National Drug Control Policy, in an interview yesterday in Vancouver.

About 60 per cent of six million people who need treatment services for drug abuse in the United States are dependent on marijuana, he said.

Earlier this month, Mr. Walters campaigned against measures to relax drug laws in Nevada, Arizona and Ohio.

Despite well-financed campaigns by pro-marijuana advocates, voters in those states rejected the measures.

Mr. Walters said he is making his first-ever visit to Vancouver because British Columbia increasingly supplies marijuana to Americans.

The U.S. government had succeeded somewhat in controlling the flow of drugs across its southern border with Mexico, he said.

But while it was looking south, British Columbia developed a $6-billion industry of what he described as the most potent, most commonly addictive drug in the United States.

Police told him that 95 per cent of the B.C. product is exported to the United States.

The psychoactive ingredient in B.C. marijuana is up to four times stronger than in other marijuana currently available on U.S. streets, he said.

"The problem we face is that people do not appreciate the danger that marijuana poses, particularly for young people," he said.

Mr. Walters, who is described in U.S. media as a law-and-order conservative, has advocated severe prison sentences for marijuana smugglers as well as allowing the military to play a lead role in interdiction.

He said he has not spent enough time in B.C. to fully understand what is going on in the province. However, Canada's approach to marijuana conflicts directly with Mr. Walters's views on the drug and how to deal with it.

Legalizing marijuana -- which has been recommended by a Senate committee in Canada -- is "ludicrous," he said. Allowing marijuana use for medical purposes -- which is federal policy in Canada -- is not supported by science, he said.

Despite the differences, Mr. Walters said he wants greater co-operation from Canada on enforcement of antimarijuana laws.

Earlier this year, U.S. officials reported they had seized nearly twice as much marijuana at the B.C.-Washington state border as in the year before.

Mr. Walters said targets have not been set to further reduce cross-border marijuana traffic. He anticipated that stepped-up measures introduced mostly for security reasons will have an impact on the flow of drugs through Vancouver's port and border crossings.

Offering a glimpse of what is in store, he said he expected more prescreening of commercial goods at the ports and airports.

New technology will be introduced to allow inspectors to scan shipping containers without opening them. New devices are being developed to measure gases and other emissions, he said.

Mr. Walters also anticipated more prescreening of individuals.

However, the strongest efforts to disrupt the drug trade should not be made at the border, Mr. Walters said.

"Trying to do this at the border is like trying to hit a pitch in baseball blindfolded," he said. "You may once in a while connect but it is largely going to be an accident."

He would not comment on what he expected law-enforcement agencies in Canada to do.

RCMP Constable Danielle Efford later said Mr. Walters and the RCMP "shared information and ideas" during a private informal meeting.

The RCMP is committed to work with its partners in the United States and elsewhere, she said. However, she would provide no details about the discussions.