According to recent highly classified intelligence confirmed by NBC News, Iran is trying to adapt its missiles to carry nuclear warheads.
"I'm aware of information that suggests they were working hard as to how to put the two together," Secretary of State Colin Powell told reporters traveling with him Wednesday to Chile for an Asia-Pacific economic summit.
Iran's missiles have a range of 1,000 miles and can easily reach Israel, as well as U.S. troops in the region.
The news comes just three days after Iran promised on Monday to stop producing nuclear fuel that can be used for bombs. But the Bush administration is leery of Iran's promises.
"Every civilized nation in Europe and the United Nations and everywhere else ought to be concerned that Iran is moving in the direction of acquiring nuclear weapons technology," Powell told CNBC's Maria Bartiromo last week.
In Paris on Wednesday, Iranian exiles showed aerial photos of what they claim is Iran's secret nuclear bomb facility.
"This information is 100 percent correct," says Muhammad Mohaddessin of an Iranian opposition group.
If true, it would mean that despite its denials, Iran is working on several fronts to build a bomb and a way to deliver it.
"Militarily, it means that they are working hard to master this very difficult step of taking a very large nuclear bomb and shrinking it down to a size that they could actually put on one of their missiles," says weapons expert Joseph Cirincione, director of the Non-Proliferation Project at the Carnegie Endowment for International Peace.
Still, the United States has had a hard time persuading the rest of the world to crack down on Iran, especially after the administration's bad intelligence about Saddam Hussein's nuclear weapons.