The U.S. Food and Drug Administration said Thursday it does not support "the use of smoked marijuana for medical purposes."

The FDA released a statement in Washington reiterating its long-held position that marijuana meets the three criteria for placement on Schedule I of the Controlled Substances Act -- the most restrictive classification of narcotics -- a high potential for abuse, no "currently accepted medical use" and "a lack of accepted safety for use under medical supervision."

Citing conclusions by the U.S. Drug Enforcement Agency, which administers the Controlled Substances Act, the FDA said there is "sound evidence that smoked marijuana is harmful."

The statement cited evaluations by the Substance Abuse and Mental Health Services Administration and National Institute for Drug Abuse, which "concluded that no sound scientific studies supported medical use of marijuana for treatment in the United States, and no animal or human data supported the safety or efficacy of marijuana for general medical use."

The FDA said measures in a growing number of states to legalize medical marijuana are "inconsistent with efforts to ensure that medications undergo the rigorous scientific scrutiny of the FDA approval process," and are proven safe and effective.