by JAMES DREW

Earlier this month, Defense Secretary Ashton Carter told CNN the United States military has the capability to “shut down, set back and destroy” Iran’s nuclear program.

The highly-publicized yet classified weapon Carter was referring to is the Massive Ordnance Penetrator — a behemoth, 30,000-pound bunker bomb introduced specifically to destroy Iran’s underground uranium enrichment facilities.

In January, we told you the Pentagon was modifying and testing the bomb as the diplomatic push for a nuclear settlement with the pariah state intensified. But of course, that’s not all the U.S. military has been up to in the background.

The Air Force, which leads the development of air-delivered bunker bombs, is preparing to go shopping for a new “family” of weapons to kill fortified targets — and it’s compiling that shopping list right now.

This list is likely to include a new rocket-rammed High Speed Strike Weapon for the F-35 Joint Strike Fighter, plus a new class of inexpensive, mid-weight penetrating bombs.

And as a last resort, the U.S. government is holding onto its only earth-penetrating nuclear bomb, the B61–11, even as it reduces its nuclear stockpile to comply with an arms reduction treaty with Russia.

The Air Force definitely wants to make more improvements to the Massive Ordnance Penetrator, since a third and fourth “enhanced threat reduction” modification program is included in its 2016 budget plans. The service is also about to scale up production of a smart, void-sensing fuze that counts bunker layers and detonates at the correct level.

An Air Combat Command review of the flying branch’s so-called hard-target munitions inventory recently wrapped up, and that study is circulating among senior leaders within the department and the Office of the Secretary of Defense.

The classified study assessed what the Air Force currently has, and what it might need in the future as nations like Iran and North Korea find new ways to harden their military installations against attack from the West.

The Air Force won’t say much about the study officially, but senior service officials have been dropping hints as Congress seeks assurances about the military’s ability to destroy Iran’s nuclear sites should diplomacy fail.