"This deal as far as we can see comes on almost daily concessions from the P5+1 to growing Iranian demands. Every day more concessions are made, and every day the deal becomes worse and worse," Netanyahu said Monday. "This deal will pave Iran's path to a nuclear arsenal."
Netanyahu's comments come as negotiators from Iran, the U.S. and five other world powers are racing to try and secure a final agreement that would restrict Iran's nuclear program for 15 years while also freeing Iran of the economic sanctions that have squeezed Iran's economy. Negotiators extended the talks until Tuesday, but have also indicated that deadline too is not set in stone.
Iran's Foreign Minister Javad Zarif said Friday in a video posted online that negotiators have "never been closer" to a deal and U.S. Secretary of State John Kerry said Sunday that the two sides have made progress, but still have "difficult issues to resolve."
"At this point negotiations could go either way," he told reporters on Sunday.
A senior Iranian official told CNN on Monday that there can be "further engagement and interaction" between the two sides if the U.S. makes "constructive moves."
American negotiators hope to achieve a deal before Thursday. Congress set July 9 as the date by which the Obama administration must submit a deal for a 30-day review. That period doubles if the deal is submitted after July 9, extending what would likely be a heated and divisive fight over the merits of a deal.
Iranian officials have been clear though that there is no hard deadline in the talks.
"After June 30, we don't have an agreed deadline," a senior Iranian diplomat told CNN on Monday.
Republican Sen. Bob Corker of Tennessee, who chairs the Foreign Relations Committee and authored the bill that established the July 9 date, said Sunday he urged Kerry not to focus on the deadline, but instead to "make sure these remaining red lines...do not get crossed."
Netanyahu has already made up his mind, though, before negotiators resolve the final crucial issues related to inspections and sanctions relief.
"I can say that what we see in Vienna is not a breakthrough, but more like a breakdown -- a breakdown of the principles that the P5+1 committed itself to uphold," Netanyahu said, referring to the six countries negotiating with Iran.
He warned that Iran will see billions of dollars flow in as a result of sanctions relief, buttressing its coffers to pursue its regional ambitions -- which include supporting terror groups like Hamas and Hezbollah that target Israel.
Netanyahu previously took his opposition to the Iran negotiations to Capitol Hill, where he addressed a joint session of Congress in a controversial appearance that was not coordinated with -- and opposed by -- President Barack Obama's White House.
"The conclusion is simple, its been said by many leaders, and I will say it again right now: better no deal than this very bad deal," Netanyahu said on Monday.
Both U.S. and Iranian officials have said that while they are both aiming to broker a final deal, they each have their own red lines.
U.S. officials have insisted they will walk away from a deal that does not ensure that international monitors can inspect any site in Iran for nuclear activity.
And a senior Iranian official told reporters on Monday that Iran is not "desperate" to get a deal.
"We want a deal but not at any cost," he said.