New York—The weapons Israel did not get in its most recent deal with the United States were bunker busters, bombs designed to penetrate deep into mountains and deep tunnels. Now the Wall Street Journal reports that the biggest bunker busters have been redesigned with enhancements that will allow them to penetrate Iran’s deepest and most heavily fortified nuclear site.  According to the newspaper, American and Israeli officials, as well as “civilian leaders,” were shown an Air Force video of an earlier version of such a bomb in action, and told about the improvements. The point of the exercise, according to unnamed U.S. officials, is to convince the Israelis that if and when diplomacy fails, the U.S. will have the power to prevent Iran from further developing nuclear weapons.

The bomb under discussion is a 30,000 lb. Massive Ordnance Penetrator (MOP) with increased burrowing power, a more precise guidance system and enhanced defense mechanisms—making it difficult to shoot down. Its goal would be to reach the under-the-mountain Fordow nuclear plant near the “holy” city of Qom.

The Americans and Israelis are on hold for now and will reassess Iran’s intentions sometime after the Iranian elections in June. They report that if diplomacy fails, military options will be discussed.