Los Angeles Mayor Antonio Villaraigosa on Wednesday signed into law a measure banning all medical marijuana clinics in the city.

The measure, approved by the City Council last week on a 14-0 vote, will take effect within 30 days.

The mayor's action came as organizers at Local 77 of the United Food and Commercial Workers held a private meeting to discuss plans for a referendum asking voters to keep some clinics open.

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