Bunker-buster bombs. Photo: U.S. Navy.

The massive new defense deal signed by the U.S. and Israel will not include the highly sought after “bunker-buster” bombs that Israel could use to hit Iran’s underground nuclear facilities, the New York Times reported.

Officially known as Massive Ordnance Penetrator, the bombs weigh about 30,000 pounds and are designed to penetrate earth and destroy deeply buried sites.

Termed as the “zone of immunity,” Israel is concerned that Iran will soon transfer its nuclear enrichment capabilities to an underground military site at Fordo, putting the facilities out of reach for potential Israeli bombers.

The U.S. has been reluctant to supply Israel with the massive bombs. Additionally, the U.S. has also been reluctant to sell Israel heavy aircraft such as the B-2 stealth bomber capable of carrying the weapons.

Nevertheless, the U.S. Defense Secretary Chuck Hagel said at news conference in Israel that he remains committed to maintaining Israel’s “qualitative military edge” and preventing Iran from developing a nuclear weapon.

“Iran will not be allowed to develop a nuclear weapon. Period,” Hagel said, according to the New York Times.

In related defense news, U.S. defense contractor Lockheed Martin, which produces the highly advanced stealth F-35 fighter jet, has signed a contract with Israel Aerospace Industries (IAI) to produce wings for the F-35, Israel Hayom reported. Touted as the most advanced fighter aircraft in the world, the F-35 program has been delayed by manufacturing issues and its high price tag. Israel is set to receive an order of 25 F-35s in 2016.