MEXICO CITY Mexican President Vicente Fox will sign legislation to decriminalize possession of small amounts of marijuana, cocaine and even heroin.

That's according to Fox spokesman Ruben Aguilar.

The bill was approved Friday by Mexico's Senate, despite criticism by some in the United States that it could increase problems with casual drug use by visitors or in border areas.

Currently, Mexican law allows judges to drop charges against suspects if they can prove they're addicts and an expert certifies they were found with only the amount needed for personal use.

The new bill makes the decriminalization automatic, allows so-called "consumers" as well as addicts to have drugs, and delineates specific allowable quantities, which do not appear in the current law.