The Biden administration plans to resume indirect negotiations with Iran this weekend as part of its efforts to revive the 2015 nuclear agreement, Deputy Secretary of State Wendy Sherman said on Wednesday.

Sherman made her remarks, which were first reported by Reuters, during a virtual event hosted by the German Marshall Fund, saying that “there’s been a lot of progress made” but that no agreement is finalized until the last detail is “nailed down.” 

The deputy secretary also said that the Iranian presidential elections, set to take place next week, have complicated the Vienna negotiations among the U.S., Iran and participants to the nuclear deal, formally called the Joint Comprehensive Plan of Action (JCPOA).

State Department spokesperson Ned Price on Wednesday said these will be the sixth round of discussions among the U.S. side, led by special envoy Robert Malley. The U.S. is in talks with European intermediaries and Iran on a pathway to “compliance for compliance” for both sides to return to the parameters of the nuclear accord.

Iran has called for the U.S. to lift all sanctions imposed after then-President Trump pulled out of the deal in 2018, in exchange for Tehran reversing actions it has taken that have violated the terms of the deal, including enriching uranium beyond the levels it allows. 

The U.S. has said it is prepared to lift sanctions that are “inconsistent” with the original terms of the JCPOA. 

“I hope we can get to compliance for compliance,” Sherman said, adding that the administration also seeks a commitment from Iran to address other areas of concern for the U.S. and its allies, such as its support for terrorist attacks and proxy fighting forces in the region, human rights abuses, missile development and detaining American citizens.

The administration’s push to rejoin the JCPOA faces deep divides on Capitol Hill, where Republicans have dug in opposing lifting the Trump sanctions and the Biden team's strategy of rapprochement with Iran, as well as warning of risks to Israel and its relationship with the U.S.

“We both know, and the world knows, that there’s another entity that’s going to do something about this whatever the JCPOA says or doesn’t say, whatever everybody else agrees to, there’s another entity that has taken a solemn oath that Iran will never have a nuclear weapon and I guess the biggest question will be, what happens when you get the call, ” Sen. James Risch (R-Idaho), ranking member of the Senate Foreign Relations Committee, said in a hearing with Secretary of State Antony Blinken on Tuesday. 

While the majority of Democrats have put their support behind the administration’s efforts, top Democratic senators including Foreign Relations Chair Bob Menendez (N.J.), who originally opposed the JCPOA, are raising concerns over the Biden administration's ability to follow through on addressing the shortfalls of the deal. 

“I hope, Mr. Secretary, that as we are assuaging our European colleagues and our cohorts in this effort, that they are truly committed to the ‘stronger’ part,” Menendez said in the hearing with Blinken, “because my experience with them is they want to solve the immediate problem, but getting them to follow on on the longer-term problems is a much more difficult proposition.”

Updated Thursday at 9:02 a.m.