U.S. President Barack Obama and his Russian counterpart, Dmitry Medvedev, may have signed a landmark arms-control treaty, but a U.S. think tank is suggesting Israel could resort to using tactical nuclear weapons to destroy Iran's deeply buried nuclear facilities.

Whether this is all part of a U.S. effort to crank up the pressure on Iran to be more compliant on the nuclear issue by using scare tactics or if the right-wing government in Israel is actually inclined to resort to nuclear weapons is almost impossible to discern.

But one day after the Center for Strategic and International Studies in Washington released a report on March 26 noting that "some believe that nuclear weapons are the only weapons that can destroy targets deep underground or in tunnels," The New York Times reported Iran was suspected of preparing to build two more uranium enrichment plants.

And just to ram the message home, on March 28, the Times' Sunday edition ran an analysis headlined "Imagining an Israeli Strike on Iran."

The 208-page report, by veteran Middle East analysts Anthony Cordesman and Abdullah Toukan, argued that Israel's air force does not have the firepower to knock out the Iranian facilities and that low-yield tactical nuclear warheads would be the only way to destroy them.

Israel, of course, has made no comment on this at all, in line with its policy of deliberate ambiguity about its nuclear arsenal, believed to total some 600 warheads, bombs and artillery shells.

Nor does it discuss its inventory of Jericho II -- and probably some Jericho III -- ballistic missiles capable of carrying nuclear warheads. These are placed in heavily fortified silos in the Judean Hills and near two or three Israeli air bases.

But if Israel elected to launch a nuclear strike, it is likely that the Jerichos would be the chosen means of delivery.

They would eliminate Israeli casualties, of which there would be an appreciable number if the air force was thrown at Iran's heavily protected nuclear infrastructure, and the loss of valuable strike aircraft.

One assessment estimated Israel would need 90-100 long-range F-15I and F-16I aircraft for such strikes, of which around 20 percent would be lost.

In an assessment in March 2009, Toukan estimated that 42 Jericho IIIs, with 1,650-pound conventional warheads, would be needed to "severely damage or demolish" Iran's core nuclear facilities at Natanz, Isfahan and Arak.

That, according to most estimates, would be enough to set back Iran's nuclear arms project by two or three years.

But it would also run the risk of retaliatory attacks on Israel, either with Iran's Shehab-3 intermediate-range ballistic missiles -- Tehran has threatened to unleash 600, although there's no evidence it has that many -- or using local proxies Hezbollah and Hamas.

Israel could also use its three German-built Dolphin-class submarines, reportedly adapted to launch nuclear-tipped cruise missiles, firing from the Arabian Sea to add to the mayhem.

Little is known about the Jericho III, but it is believed be a three-stage, solid-fuel missile capable of carrying a nuclear warhead for a minimum range of 2,980 miles.

Israel has never even hinted at using nuclear weapons against Iran.

President Shimon Peres, who played a key role in creating Israel's nuclear capability in the 1950s and 60s, has declared the Jewish state "will not be the first to introduce nuclear weapons to the region."

The Americans have repeatedly warned Israel not to mount unilateral pre-emptive strikes against Iran because that could drag the United States into another war.

Obama's new version of U.S. nuclear strategy unveiled Tuesday significantly narrows the circumstances in which Americans would employ nuclear arms. But it does allow their use against rogue states like Iran.

While that's hardly a green light for Israel, former Central Intelligence Agency official Philip Giraldi notes: "Israel is fast becoming a pariah nation … Like South Africa, the Israeli response to criticism has been to become more reactionary … waging unending war against its neighbors to maintain cohesion against foreign enemies.

"There is a certain danger in isolating the Israelis too much as it … might influence a dangerously unstable government to take action that might include exploiting its nuclear arsenal in search of Armageddon."