Obama urged to back tough arms trade treaty at U.N. talks UNITED NATIONS (Reuters) - Three dozen arms control and human rights groups have written to U.S. President Barack Obama ahead of new arms-trade negotiations at the United Nations next month, urging him to back a tough treaty that would end loopholes in international weapons sales. Arms control campaigners say one person every minute dies worldwide as a result of armed violence and a convention is needed to prevent the unregulated and illicit flow of weapons into conflict zones and fueling wars and atrocities. The U.N. General Assembly voted in December to restart negotiations in mid-March on what could become the first international treaty to regulate the $70 billion global arms trade after a drafting conference in July collapsed because the United States and other nations wanted more time. "The United States, as the world's leading arms supplier, has a special responsibility to provide the leadership needed for an ATT (arms trade treaty) with the highest possible standards for the transfer of conventional arms and ammunition," the groups wrote to Obama in a letter delivered late on Friday. "The Arms Trade Treaty can provide a key tool to help reduce enormous human suffering caused by irresponsible international arms transfers and arms brokering," the letter said. The 36 groups that co-authored the letter include Amnesty International USA, Arms Control Association, Friends Committee on National Legislation, Oxfam America, National Association of Evangelicals and other groups. The point of the treaty is to set standards for all cross-border transfers of any type of conventional weapon - light and heavy. It also would set binding requirements for nations to review all cross-border arms contracts to ensure the munitions will not be used in human rights abuses, do not violate embargoes and are not illegally diverted. Deputy U.S. National Security Council spokeswoman Caitlin Hayden confirmed the White House had received the letter, saying it "raises a number of important issues." She said Washington would support a treaty under certain conditions. "The March 2013 Arms Trade Treaty Conference will seek an Arms Trade Treaty that will contribute to international security, (and) protect the sovereign right of states to conduct legitimate arms trade," she said in an email that provided the most extensive public U.S. statement on the treaty in months. Hayden said Washington would not support a treaty that infringed on the constitutional right of U.S. citizens to bear arms - a sensitive political issue in America. Since adoption of a treaty next month will require consensus, the United States and all other delegations have de facto veto powers. "The U.S. objective is to bring other countries in line with existing U.S. best practices, which will have a positive humanitarian impact and reduce the chances that illicit arms flow to terrorists and those that would commit human rights violations," Hayden said. She also said Washington would not accept a "weak treaty." If a treaty is approved, it will require ratification by signatories' legislatures before it goes into effect. The leading U.S. pro-gun group, the National Rifle Association (NRA), has vowed to fight hard to prevent ratification of the treaty if it reaches Washington. The treaty's supporters accuse the NRA of deceiving the U.S. public about the pact, which they say would have no impact on domestic gun ownership and would only apply to exports. The main reason the arms trade talks are taking place at all is that the United States - the world's biggest arms trader, which accounts for more than 40 percent of global transfers in conventional arms - reversed U.S. policy on the issue after Obama was first elected and decided in 2009 to support a treaty. The authors of the letter called on Obama to ensure that any approved treaty requires exporting states to "assess the risk of a proposed export being used to commit or facilitate a serious violation of international human rights or humanitarian law, or acts of terrorism." They also urged the United States not to back exclusion of ammunition from the arms trade treaty, which will be negotiated by about 150 countries at U.N. headquarters March 18-28. "The exclusion of ammunition from the scope of the treaty would greatly reduce the treaty's ability to achieve many of its most important goals," the groups wrote, adding that the United States already licenses the import and export of ammunition. But the White House made clear it would continue to oppose the inclusion of ammunition in the draft treaty. "Ammunition is a fundamentally different commodity than conventional arms," Hayden said. It is fungible, consumable, reloadable, and cannot be marked in any practical way that would permit it to be tracked or traced. Reporting By Louis Charbonneau; Editing by Bill Trott