The United States on Wednesday became the 91st state to join a landmark global arms trade treaty strongly opposed by North Korea, Iran and Syria. Signing the Arms Trade Treaty at the United Nations, Secretary of State John Kerry described it as an \"important step\" toward a more peaceful world. \"This is about keeping weapons out of the hands of terrorists and rogue actors,\" he said. \"This is about reducing the risk of international transfers of conventional arms that will be used to carry out the world\'s worst crimes.\"    It prohibits states from transferring conventional weapons to countries when they know those weapons would be used to commit or facilitate genocide, crimes against humanity or war crimes. To be affected is the trade of battle tanks, armored combat vehicles, large-caliber artillery systems, combat aircraft, attack helicopters, warships, missiles and missile launchers, and small arms and light weapons. The Barack Obama administration\'s decision is expected to provide momentum to efforts to put the treaty into effect. The U.N. General Assembly adopted it in April, although three nations -- North Korea, Iran and Syria -- voted against it. It remains uncertain whether and when U.S. Congress will ratify it. Conservative Republican lawmakers in particular have taken a dim view of the treaty, claiming it could trigger new gun control measures. The National Rifle Association also said it will be used to regulate civilian weapons and to create an“unacceptable\" registry of civilian firearms purchasers. Administration officials deny that. The treaty is aimed at curbing illegal trade in conventional weapons, while protecting the freedom of individuals and states to obtain and use arms for legitimate purposes, they said. The treaty requires ratification by at least 50 states to take effect but only four nations have done so so far. They are Iceland, Nigeria, Guyana and the Caribbean island state of Antigua and Barbuda On average at least 500,000 people reportedly die every year and millions more are displaced and abused as a result of global armed violence and conflict.