The United States is concerned over reports that Iranian-made weapons are making it across the Afghan border and into the hands of Islamist Taliban insurgents, a top U.S. diplomat said on Tuesday( September 11). Iran supported Afghan groups fighting the Taliban in the 1990s and played a crucial role in helping to topple the Taliban's Sunni government, ousted by the 2001 U.S.-led invasion, by supporting their Mujahideen foes. The Shiite Islamic Republic has repeatedly in the past denied accusations by U.S. officials that it is arming the resurgent Taliban, who are largely active in southern and eastern areas close to the border with Pakistan. "Yes we are concerned by reports, which we consider to be reliable, of Iranian explosively formed projectiles and other kinds of military equipment coming from Iran across the border and coming into the hands of the Taliban that is a source of concern us." said U.S. Deputy Secretary of State John Negroponte at a news conference in Kabul Negroponte did not elaborate. The Taliban, like the Iranian government, have rejected U.S. reports about its acquiring Iranian arms and Afghan President Hamid Karzai has hailed relations with Iran as good. Violence has surged in Afghanistan in the past 19 months, the bloodiest period since the Taliban's ouster.