The United Nations has renewed its warnings to Uruguay and the US states of Colorado and Washington that their cannabis legalisation policies fail to comply with the international drug treaties.

The U.S. Government has signalled discomfort with Jamaica's move to decriminalise marijuana for specific uses.

The head of the International Narcotics Control Board (INCB) monitoring compliance with international drug control conventions expressed concern about the moves by U.S. states to legalize marijuana.

The director of the United Nations Office on Drugs and Crime, Yury Fedotov, said that state-level marijuana legalization initiatives in the U.S. are violations of longstanding international drug treaties. "I don't see how [state-level marijuana legalization] can be compatible with existing conventions," he said according to Reuters. Fedotov's remarks are coming less than a month after Assistant Secretary of State Brownfield outlined an official policy of "flexibility" in the U.S.'s interpretation of existing U.N. drug control conventions, which require countries to outlaw the sale and use of cannabis. (See also: Fatal attraction: Brownfield's flexibility doctrine and global drug policy reform)

The UN's top narcotics official said on Wednesday that recent votes by US states to legalize marijuana have put America in deeper violation of the international conventions that guide drug policy around the world. Earlier this month, voters in Oregon, Alaska, and Washington DC legalized the recreational use and sale of marijuana. Similar ballot initiatives have already passed and taken effect in Colorado and Washington.

Moves by some U.S. states to legalize marijuana are not in line with international drugs conventions, the U.N. anti-narcotics chief said, adding he would discuss the issue in Washington next week. 

No pressure, Colorado and Washington, but the world is scrutinizing your every move. That was the take-home message of an event today at the Brookings Institution, discussing the international impact of the move toward marijuana legalization at the state-level in the U.S. Laws passed in Colorado and Washington, with other states presumably to come, create a tension with the U.S. obligations toward three major international treaties governing drug control.

Legalisation of cannabis is making slow but unstoppable progress across much of the developed world, many experts believe, following the end of prohibition in two US states. In Amsterdam, long famous for its coffee shops, international experts gathering to discuss cannabis regulation said the international conventions, once so heavily policed by the US, would now be increasingly flouted. Already many countries, most notably the Netherlands and Spain, have bypassed the rules.

Eight former Drug Enforcement Administration chiefs warned the federal government that time is running out to nullify Colorado and Washington's new laws legalizing recreational marijuana use, and a United Nations agency also urged challenges to the measures it says violate international treaties. 

A whiff of change is in the air regarding drug control policy. Officials in two American states, Colorado and Washington, are pondering how to implement their voters’ decisions last November to legalise cannabis. One immediate consequence is that the United States will be in breach of the UN Convention. Good. It should now join Latin American governments in an effort to reform that outdated document to allow signatories room to experiment. Imposing a failed policy on everybody benefits nobody.

The President of the International Narcotics Control Board (INCB), Raymond Yans, has voiced grave concern about the outcome of recent referenda in the United States of America that would allow the non-medical use of cannabis by adults in the states of Colorado and Washington, and in some cities in the states of Michigan and Vermont. Mr. Yans stated that “these developments are in violation of the international drug control treaties, and pose a great threat to public health and the well-being of society far beyond those states”.