Defense Secretary Ash Carter said Friday the Pentagon had ready a bunker-busting bomb that could destroy Iran’s underground nuclear facility, in case the U.S. ever had to resort to a military option to stop Iran from developing a nuclear weapon.

“We continue to improve it and upgrade over time so that there is this alternative,” Carter said in an exclusive interview with CNN’s “Erin Burnett OutFront,” referring to a weapon called the Massive Ordnance Penetrator.

U.S. and international negotiators have until June 30 to reach a final deal with Iran, which would exchange sanctions relief for limits on Iran’s nuclear program, which they believe is for a nuclear bomb. […]