WASHINGTON -- Obama administration officials are now publicly lobbying against a bill in the US Senate that would double down on sanctioning Iran just as bilateral negotiations have resumed between the two nations.

Since the first round of Geneva talks last month, the Obama administration has asked Congress to pause any work on new legislation that would impose additional penalties on the Islamic Republic for continuing work on its expansive nuclear program.

"We asked for a pause, to provide flexibility, of new sanctions," State Department spokeswoman Jen Psaki said on Wednesday. "We believe that congressional action needs to be aligned with our negotiating strategy."

Secretary of State John Kerry and Treasury Secretary Jack Lew will be on Capitol Hill on Thursday afternoon, where they will brief Senate leadership behind closed doors on developments with Iran in an effort to dissuade them from moving forward with the bill.

The Senate legislation targets roughly half of what remains of Iran's oil exports, cutting their sales of crude to less than 500,000 barrels a day. That is a significant reduction from what was proposed in a bill that passed the House of Representatives last August, which would cut virtually all of Iran's remaining exports down to zero.

The White House has urged legislators to water down the bill, but concurrently aims to delay its passage. If given a vote, the bill would likely pass with bipartisan support.

Senator Robert Menendez, chairman of the Foreign Relations Committee and an active proponent of the new penalties, told the American Israel Public Affairs Committee on Monday that the Senate would only consider halting additional sanctions if Iran completely froze its uranium enrichment work.

"We can’t want a deal more than the Iranians and we can’t be so anxious for a deal that we weaken our hand at a moment when we hold the best cards," Menendez said.

The administration fears the bill might backfire: effective sanctions require cooperation from the international community, and many allies might see the new bill as a sign that the US is not truly interested in a peaceful solution to the slow-motion nuclear crisis.

Furthermore, Iran's conservative political wing would likely seek to punish President Hassan Rouhani for pursuing diplomacy with the US if he returns from direct talks only with harsher penalties to show for them.

"When I began this drive, I was told that it wouldn’t work– that other nations wouldn’t comply, and that you couldn’t force Iran back to the table," Menendez said. "The fact is they were wrong then and they are wrong now."

National security advisor Susan Rice, her deputies Ben Rhodes and Tony Blinken and Deputy Secretary of State Wendy Sherman met with the leaders of four major American Jewish organizations on Tuesday afternoon in an effort to dissuade them from lobbying the Senate towards passing the harsh new sanctions bill.

The White House meeting with leaders of AIPAC, the American Jewish Committee, the Anti-Defamation League and the Conference of Presidents of Major American Jewish Organizations witnessed forceful exchanges between the two sides on the merits of the sanctions package, sources told The Jerusalem Post.

The afternoon meeting lasted over an hour and was characterized as a "serious exchange" over strategy during the delicate diplomatic window. One White House official called the meeting "constructive" and said there was no animus between the two parties.

"We have not rolled back any existing sanctions, and we're not doing anything to impact our core sanctions," Psaki said.

"The administration has been able to buy itself roughly two weeks before the pressure will reach an extreme point," one Senate aide familiar with the consultations told The Post. The next round of talks between Iran and the P5+1— the US, United Kingdom, France, Russia, China and Germany— will be held in Geneva on November 7.

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