Carl Levin (D-Mich.), chairman of the Senate Armed Services Committee, said Friday, Nov. 1, that Congress should not pass new sanctions against Iran while the Barack Obama administration “tests” the chances for a nuclear agreement with the Islamic Republic.

Speaking at the Council on Foreign Relations in Washington a day after Vice President Joe Biden, Treasury Secretary Jack Lew and Secretary of State John Kerry briefed senators on the current negotiations, Levin said he did not know whether the softening of Iranian rhetoric since the election of President Hassan Rouhani represented “real change.” But, he added, “Whether it is a 10%, 40% or 60% chance [that the change is real], it should be tested and probed. We should not at this time impose additional sanctions.”

As Levin spoke, technical experts from Iran, the United States and the other permanent members of the UN Security Council plus Germany were concluding two days of talks in Vienna on the details of an Iranian proposal tabled in Geneva last month. Iranian officials also met earlier this week with Yukiya Amano, the head of the International Atomic Energy Agency (IAEA), and reportedly made a new offer to clarify long-standing disagreements with the IAEA about Iran’s past nuclear work.

Amano, speaking at the Woodrow Wilson International Center for Scholars later Friday, said Iran "made a proposal that contains real substance" after years of "going around in circles" in talks with the IAEA. He did not provide details on whether Iran had agreed to live streaming of its nuclear facilities with remote cameras. He did say that Iran was no longer tying progress on resolving questions about possible military dimensions of its program to the broader talks about a nuclear agreement.