White House spokesman Jay Carney said new sanctions would be most effective as a consequence for Iran refusing to accept a deal or forsaking its commitments under an agreement.
Undeterred, a group of Republican senators led by Sen. Mark Kirk, R-Ill., pushed ahead with a new round of sanctions, circulating a letter to other senators asking for support in adding the sanctions to a defense bill. But the amendment had little chance of coming up for a vote before the Senate's Thanksgiving recess, leaving time for a deal to be reached before new sanctions would be finalized.
Separately, in a letter to Secretary of State John Kerry after the meeting, six senators from both parties cast doubt on the budding deal, urging the Obama administration not to accept an agreement that would be overly generous to Iran or insufficiently tough on its nuclear program. Among those signing the letter were Obama allies Sen. Chuck Schumer, D-N.Y., and Sen. Bob Menendez, D-N.J., chairman of the Senate Foreign Relations Committee.
In the letter, the senators cited specific concerns about nuclear activities Iran would continue to be allowed to conduct, such as enriching uranium at certain levels and maintaining its current number of centrifuges.
"We regard this as a major concession on our part that would not be justified by the concessions the Iranian regime would be required to make in return," the senators wrote. "If we are reducing sanctions, Iran should be reducing its nuclear capabilities."
Obama convened the meeting one day before the U.S. and five other world powers resume talks with Iran in Geneva.