VIENNA — Negotiators from Iran and six world powers may “stop the clock” for a day or two if they run up against a self-imposed July 7 deadline to conclude a final Iran nuclear deal, as diplomats said they had made significant progress here on the text and annexes of the accord, even while they still had important differences to overcome. 

“We have made good progress on almost all of the issues,” a senior Iranian negotiator said July 6. “But there are a few issues which … remain to be resolved. Probably those issues need to be resolved at the ministerial level.”

“They are tough issues,” the Iranian official, speaking not for attribution, told foreign journalists in Vienna on July 6. “Hard decisions have to be made at the end of the day,” he added, echoing US Secretary of State John Kerry’s comments on the talks the day before.

But negotiators made clear they hope to conclude the accord the next few days in Vienna versus going home and coming back again, at the risk of losing momentum and having to renegotiate issues they thought were already solved, as has happened in some past negotiating rounds. They also acknowledge that they prefer to finish the deal if at all possible by July 9, which is now considered the drop-dead date by which the US administration would need to have the deal in hand in order to submit it to Congress by a July 10 deadline, after which Congress would get 60 days versus 30 days to review it.