A top Pentagon official said Monday that a US missile defense drill would simulate an Iranian attack - a departure from the usual scenario of a North Korean attack - according to Reuters. "Previously, we have been testing the [Ground-Based Midcourse Defense] GMD system against a North Korean-type scenario. This next test... is more of a head-on shot like you would use defending against an Iranian shot into the United States. So that's the first time that we're now testing in a different scenario," Lt.-Gen. Patrick O'Reilly, head of the US Missile Defense Agency, said at the Reuters Aerospace and Defense Summit in Washington. According to O'Reilly, an Iranian attack would be more challenging than a North Korean attack because a missile fired from Iran would reach the US "more head-on than from the side," and therefore relatively faster. The test, scheduled for January, is expected to cost about $150 million. During the maneuver the US will fire an interceptor missile from Vandenberg Air Force Base in California at a mock-Iranian missile which would be fired from the Marshall Islands in the Pacific Ocean. O'Reilly was speaking just days after diplomats expressed concerns over reports that Iran had been testing a neutron initiator, a key element in producing nuclear weapons. A neutron initiator begins the implosion that ends with a nuclear blast. As a component of the nuclear cycle, it has no use in civilian or military programs, except in the production of atomic bombs. On Sunday, Britain's Times claimed it had obtained confidential intelligence documents from "foreign intelligence agencies" and quoted a source at an "Asian intelligence agency" as confirming that Iran had been working on the device "as recently as 2007." If the report is correct and Iran began developing the device while insisting its program was peaceful, it could be a casus belli, Mark Fitzpatrick, senior fellow for non-proliferation at the International Institute for Strategic Studies in London, was quoted by the Times as saying. "If Iran is working on weapons, it means there is no diplomatic solution," he said, adding, "Is this the smoking gun? That's the question people should be asking. It looks like the smoking gun. This is smoking uranium."