Western intelligence experts told Newsweek that if an Israeli strike on Iran's nuclear facilities is to cause any real damage the Jewish state will have to use its own nuclear weapons.
The experts noted that in order to slow down or destroy Iran's nuclear program, there are four key sites Israel needs to hit. However, all four are buried deep underground and protected by more than 60 feet of concrete.
The only ways to effectively damage the sites are to hit them with several bunker-buster bombs at exactly the same point - a difficult feat to accomplish - or employ tactical nuclear weapons.
The sources said they do not believe it likely that Israel would ever be the first to use nuclear weapons in a confrontation with any of its neighbors.
Israel has, however, been pushing its Western allies to keep the military option for dealing with Iran's nuclear program on the table, and has even indicated that it is prepared to go it alone if necessary.
Earlier this year, Israel held a massive air exercise over the eastern Mediterranean that purportedly simulated a long-range strike on Iran.
Israel later reportedly requested a flight corridor through US-controlled Iraqi airspace, a request that was rejected.