(Reuters) - Moves by some U.S. states to legalize marijuana are not in line with international drugs conventions, the U.N. anti-narcotics chief said on Wednesday, adding he would discuss the issue in Washington next week. Residents of Oregon, Alaska, and the U.S. capital voted this month to allow the use of marijuana, boosting the legalization movement as cannabis usage is increasingly recognized by the American mainstream. "I don't see how (the new laws) can be compatible with existing conventions," Yury Fedotov, executive director of the United Nations Office on Drugs and Crime (UNODC), told reporters. Asked whether there was anything...