The United States boosts the output of a massive 30,000-pound bomb that can hit Iran's underground nuclear facilities. The 30,000-pound Massive Ordnance Penetrator, known as a bunker-buster, can be dropped only from a B-2 stealth bomber. US State Department on May 13 said "Biden and Blinken will not allow Iran to have a nuclear weapon" in response to a question after Iran's Supreme leader Ayatollah Ali Khamenei's advisor Kamal Kharrazi said Tehran would have no option but to change its nuclear doctrine in the face of Israel's threats. Watch