Israel’s spy chief Dan Meridor received assurances from President Barack Obama the U.S. government is committed to preventing Iran from gaining nuclear weapons.

The Jerusalem Post  said Meridor met with Obama at the Nuclear Security Summit in Seoul. Meridor said the U.S. understands Iran can't be permitted to make nuclear weapons despite sanctions against it, as what happened with North Korea. Prevention is the policy of Washington.

Meridor told Israel Radio Tuesday following the closed door meeting, The line that Obama draws is clear -- both with North Korea and with Iran.

The U.S. might seek Russia’s help in persuading Iran to give up its nuclear ambitions, by joining in the economic sanctions already being applied by the West, Meridor added; however, he declined to discuss what was said behind closed doors.

The summit was attended by leaders from nearly 50 countries, including China and India, to discuss ways to reduce nuclear threats as more nation's claim the capability. “These dangerous materials are still vulnerable in too many places,” Obama said.

“It would not take much, just a handful or so of these materials, to kill hundreds of thousands of innocent people and that’s not an exaggeration, that’s the reality that we face. The threat remains. That’s why what’s required continues to be a serious and sustained effort.”

Obama has urged Israeli Prime Minister Benjamin Netanyahu to give sanctions against Iran time to work. While Obama reiterated his preference for a diplomatic solution to Iran, he seemed to take a tougher tone on Iran. I believe there is a window of time to solve this diplomatically, but that window is closing, Obama told reporters Sunday.

Meridor seemed encouraged by Obama’s more hawkish tone.

He said for the first time that he is taking a military option into account, Meridor told Israeli media. In other words, he ruled it in, after [previously saying] he doesn't rule it out.

The International Panel on Fissile Materials, an independent group of scientists and policy analysts, and the Federation of American Scientists,  a nonpartisan policy institute based in Washington, have estimated that there are nearly 20,000 nuclear warheads in the world, with about half of them in Russia. Israel is believed to have about 80 nuclear warheads.

The International Panel on Fissile Materials, however, claims there is enough stockpiled weapons-grade nuclear material left over from decommissioned bombs and atomic-fuel plants to manufacture at least another 100,000 new nuclear bombs.