Officials send warning letters to property owners and operators of an additional 67 dispensaries, giving them two weeks to comply with federal law.

Los Angeles Times: Federal officials brought their war on medical marijuana dispensaries to Los Angeles on Tuesday, raiding several shops and issuing warning letters to dozens more.

Officials at the U.S. attorney's office said it was the first large-scale federal action taken against cannabis shops in the city, and said more will probably follow. "We couldn't do all of L.A. at once," said Thom Mrozek, a spokesman for the office. "There's just too many stores."

The crackdown adds a dramatic element to the already tense fight over the fate of medical marijuana dispensaries in the city. And it underscores the stern stance of the federal government that the sale and distribution of cannabis is illegal, no matter what cities do to try to regulate the industry.

Over the last year, federal authorities have targeted pot businesses across California, including a high-profile raid at a marijuana trade school in Oakland, where proceeds on medical marijuana are taxed.

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