Negotiations to restart the 2015 Iran nuclear deal are coming to an end, but it is unclear whether they will lead to an agreement between Tehran and world powers, a senior EU official said, Reuters reported.

"We are very, very advanced in the negotiations. We have had a round of so-called proximity talks in Doha; they produced no results and the reason is very clear because we have negotiated everything that was on the table," the official said.

France's foreign minister said this week that there are only a few weeks left to reopen the deal, and Iran must decide whether to sign what was agreed upon.