Pope Francis on Friday called the legalization of drugs for recreational use "highly questionable," saying the move fails to get the desired result.
"Let me state this in the clearest terms possible: the problem of drug use is not solved with drugs," he said in Vatican City, according to The Associated Press.
Colorado recently became the first location in the world to regulate the sale of legal marijuana. A number of other states have decriminalized the drug.
Appearing to refer to more addictive drugs, Francis said legalization to provide drugs to addicts is a "veiled means of surrendering to the phenomenon."
Polling has found a majority of people in the United States believe marijuana should be legal. The Justice Department has said it will not prioritize prosecution of the recreational use of the drug in some states and President Obama has expressed willingness for legalization to go forward in some states.
Potential presidential candidate Hillary Clinton recently weighed in on the issue, saying she would want to see how legalization plays out in Colorado and Washington before she comes down on either side of the issue.
"States are the laboratories of democracy," Clinton said. "I want to wait and see what the evidence is."