The Guardian reports today that the International Atomic Energy Agency has asked Iran to explain evidence that Iranian scientists have experimented with an advanced nuclear warhead design, but Tehran continues to stonewall requests for relevant information and drag its feet at the sputtering talks over its illicit nuclear weapons program. According to a dossier prepared by the IAEA, Iranian scientists may have tested high-explosive components of a “two-point implosion” device that could enable Iran to eventually install small nuclear warheads on its ballistic missiles. One European official said that “It is breathtaking that Iran could be working on this sort of material.” The article reported on speculation that the Pakistani nuclear proliferator A.Q. Khan or a Russian weapons expert may have helped the Iranians to master the synchronized high explosive detonations necessary to build the warhead.

This revelation is one more reason, if any more were needed, to doubt the validity of the controversial 2007 National Intelligence Estimate that assessed that Iran had stopped its nuclear weaponization efforts in 2003. If Tehran already had perfected such a sophisticated technology, then it could afford to suspend further experiments while it amassed the necessary quantities of high-enriched uranium, long regarded as the “long pole in the tent” and the most challenging aspect of building a nuclear weapon.

The news about warhead experiments provides further evidence that the 2007 NIE needs to reviewed and updated. Representative Pete Hoekstra has called for an independent “red team” to examine recent revelations about Iran’s nuclear program and reevaluate the NIE assessment. Such a review is long overdue.

Meanwhile the nuclear talks with Iran, which were hailed not long ago as a potential breakthrough, are in danger of collapsing. The Washington Post today reported that Iran is balking at further talks and now insists that it must receive a full supply of nuclear reactor fuel for its Tehran research reactor before it gives up any of its low-enriched uranium stocks. This is further evidence that Tehran is backtracking on its on-again-off-again “agreement in principle” to send about 70 percent of its LEU supplies out of the country. Buried in last paragraph of the article is the fact that Iran has refused to put its uranium enrichment activities – the principal focus of the nuclear talks – on the agenda!

For more on Iran, see: Iran Briefing Room