OAKLAND (AP) — Oakland City Attorney John Russo said he will no longer advise the City Council about its plans to license large-scale marijuana farms.

In a letter to Mayor Jean Quan and each council member dated Thursday, Russo is not specific about what prompted him to make the move.

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He cites state professional conduct rules and the council’s efforts this week to redraft its proposed pot-farm ordinance to address state and federal law enforcement officials’ concerns about its legality.

In July, Oakland became the first city in the country to authorize the licensing of marijuana cultivation operations.

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Russo’s office declined to comment on the letter.

Councilwoman Jane Brunner said Russo has an obligation to advise the council. Brunner said any money to hire outside counsel should come from Russo’s budget.

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