Uruguay's Senate gave final approval on the government-sponsored bill on Tuesday pioneering a social experiment that will be closely watched by other nations debating drug legalization.

The new law, passed 16 to 13, gives the government "control and regulation of the activities of import, export, planting, cultivation, harvesting, production, acquisition in any capacity, storage, marketing and distribution of cannabis and its derivatives."

The bill must only now be signed by President Jose Mujica, who has supported the bill despite public opposition. The measure was Mujica's response to what some experts consider a failing battle against illegal drugs.

Uruguay's drug control agency will have 120 days to draft regulations imposing state control over the entire market for marijuana, from seed to smoke.

The law will allow adults to purchase up to 40 grams of marijuana monthly from pharmacies, or grow up to six cannabis plants at a time at home as licensed growers.

Possession of marijuana for personal consumption is already tolerated in Uruguay.

The law could take effect as early as mid-2014.

hc/lw (Reuters, AFP, AP, dpa)