ABC News' Jessica Yellin Reports: White House Press Secretary Tony Snow today defended the Bush administration's allegations that Iran has smuggled explosives and weapons into Iraq for the purpose of killing and wounding U.S. troops.Snow was responding to comments made by Iranian President Mahmoud Ahmadinejad this morning on Good Morning America in an exclusive interview with ABC News' Diane Sawyer, where Ahmadinejad said that Iran has asked for peace and was against conflict of any kind. "Well, the way for them to stand for peace is to make sure that there are no shipments of weapons and no shipment, also, of support for those who are trying to kill Americans or to destabilize the democracy in Iraq," Snow said of Iran at a morning briefing with White House reporters. Over the weekend, senior U.S. military officials in Iraq held a media briefing where they presented rocket-propelled grenades, mortar shells and other weapons, that they said were manufactured in Iran and supplied to Shiite militias in Iraq for attacks on U.S. and Iraqi troops. But in an interview with ABC's Diane Sawyer, the Iranian President refused to address accusations that his country was supplying weapons to insurgents in Iraq."I think that Americans have made a mistake in Iraq and unfortunately are losing, and this is a shame for Americans of course and that's why they are trying to point their fingers to other people and pointing fingers to others will not solve the problem," Ahmadinejad told ABC News. Over the weekend, the Iranian President offered to resume negotiations on Iran's nuclear program. However, Snow said that wasn't enough."The Iranians know not merely what they need to say, but what they need to do," said Snow. "We'd help them develop civil nuclear power, which is, as Diane Sawyer heard today from a number of people in Iran, they want to have," said Snow. But, "they ought to be able to have nuclear power without having the capacity to develop nuclear weapons with the ability to threaten their neighbors." said Snow. For more of Diane Sawyer's EXCLUSIVE interview with Iranian President Mahmoud Ahmadinejad, click here.