Israeli leaders have concluded that conventional air strikes would be insufficient in curbing Iran’s nuclear program, leaving only a deployment of either tactical nuclear weapons or ground forces, according to a report in the British Sunday Times.

Western “defense experts” quoted by the report pointed at the Iranian Fordo facility, which is located deep underground near the city of Qom, as a site that was immune to conventional air strikes.

“The only way to finish off Iran’s nuclear program is by using the nuclear option,” said IDF Chief of General Staff Dan Halutz, the only named source quoted by the report. “But I hope Bibi [Prime Minister Benjamin Netanyahu] is not mad enough to think about it.”

According to foreign reports, Israel is in possession of a significant arsenal of nuclear weapons, including tactical weapons such as neutron bombs, along with long-range Jericho missiles to deliver them.

Israel also possesses GBU-28 bunker-buster bombs that could be deployed by the Israel Air Force’s F-16 bombers. However, according to assessments, these bombs would not prove sufficient to penetrate the Fordo facility.