Russia on Monday said it had reason to expect some progress on the revival of a 2015 nuclear deal with Iran and that the likelihood of reaching an agreement had increased, the RIA news agency reported, citing Deputy Foreign Minister Sergei Ryabkov.

Talks have resumed in Vienna to try to revive the nuclear pact, with both sides trying to gauge the prospects of success after the latest exchanges in the stop-start negotiations.

Iran said on Sunday that European countries had failed to offer constructive proposals to help to revive the deal, after Britain said there was still time for Tehran to save it but that this was the last chance.

“European parties fail to come up with any initiatives to resolve differences over the removal of sanctions (on Iran),” Iran’s top negotiator Ali Bagheri Kani said, according to Iran’s state-run Press TV. He was referring to Britain, France and Germany, which are among the major powers trying to salvage the deal.

Under an original deal that then-US President Donald Trump abandoned in 2018, Iran limited its nuclear program in return for relief from US, European Union and UN sanctions.

The current round of talks in Vienna follow a pause of five months after the election of hardliner Ebrahim Raisi as Iran’s president.

Iranian officials have previously said they were sticking to their tough stance.