Israel tried to stave off an emerging agreement between Iran and global powers aimed at preventing Tehran from attaining a nuclear weapon, underlining the chasm that has opened up between the Obama administration and its closest Middle East allies over how to deal with their nemesis.

Israeli Prime Minister Benjamin Netanyahu railed against the expected accord in particularly harsh terms Friday, calling on Western allies to "reconsider'' after three meetings in two days with Secretary of State John Kerry. President Barack Obama called the Israeli leader in an attempt to calm the furor.

"The deal that is being discussed in Geneva right now is a bad deal,'' Mr. Netanyahu said in Tel Aviv after meeting with Mr. Kerry. "Iran isn't even required to take apart even one centrifuge, but the international community is relieving sanctions on Iran.…I urged Secretary Kerry not to rush to sign—to wait, to reconsider. To get a good deal.''

Criticism surfaced in Washington as well, where both Republican and Democratic supporters of Israel said the agreement in the works was far too easy on Iran.

Nonetheless, the U.S. and its European allies, who are partners in the deal with Iran, hoped to complete the agreement over the weekend.