United States government prosecutors have announced a crackdown on what they call California's massive commercial marijuana trade.
That includes medical cannabis dispensaries they say are often fronts for illegal for-profit drug distribution.
The move marks an escalation in friction between the federal government and California, which in 1996 became the first state to decriminalise medical marijuana.
Fifteen other states and the District of Columbia have since enacted similar statutes, though cannabis remains classified as an illegal narcotic under US law, reports Reuters.
Prosecutors say California's medical marijuana law has given cover for large-scale commercial operations to engage in drug trafficking across state lines, with large amounts of marijuana worth tens of millions of dollars flowing across the country from California.
