At the United Nations, Secretary General Kofi Annan urged the United States and Russia to reduce their nuclear arsenals. Annan’s call came during the opening day of a month-long review of the Nuclear Nonproliferation Treaty. Annan said “Ultimately, the only way to guarantee that they will never be used is for our world to be free of such weapons.” Under the 35-year-old treaty the world’s non-nuclear countries have pledged not to pursue nuclear arms, in exchange for a commitment from the U.S. Russia, Britain, France and China–to move toward nuclear disarmament. Three other nuclear states–Israel, India and Pakistan–remain outside the treaty. On Monday the nuclear countries were criticized for not moving fast enough toward disarmament. Meanwhile the U.S. and other nations called on Iran and North Korea to give up and dismantle their nuclear programs.