Netanyahu and Obama renewed their often prickly relationship in the Oval Office, meeting for the first time since their governments swapped some of the most harsh rhetoric in years over the Gaza crisis.
The Israeli leader, who is deeply skeptical of Obama's bid to broker a deal on constraining Iran's nuclear program before a deadline next month, delivered a clear signal Israel was dismayed at the outlines of a possible agreement.
"I fervently hope that under your leadership that would not happen," Netanyahu told Obama.
Netanyahu said at the United Nations this week that Iran was trying to "bamboozle" the world into sealing a nuclear deal that would leave Tehran with the capacity of thousands of centrifuges to enrich uranium.
The nuclear threshold is the point at which a nation is considered to have the radioactive material, equipment and know-how to quickly produce a nuclear device, but has not yet taken the decision to do so.
Washington wants to extract concessions from Iran to significantly expand the time it would take for the Islamic Republic to create enough fissile material to build a nuclear bomb.
Israel wants a complete dismantling of what it calls Tehran's "military nuclear program" and for Tehran to be left with zero enrichment capacity after a deal.
The US leader has said in the past that such a "perfect" deal is unlikely to be reachable.
Tehran meanwhile denies its program is intended to build a nuclear bomb.
Obama said before the Oval Office talks with Netanyahu that he would bring the Israeli leader up to speed "on the progress that has been made with dealing with Iran's nuclear program.
