Tehran: The UN nuclear watchdog’s chief will hold talks with Iranian officials in Tehran on Saturday in the hopes of salvaging a 2015 accord between Iran and world powers. The visit by International Atomic Energy Agency head Rafael Grossi is seen as critical to clinching a return to the nuclear agreement and comes parallel to negotiations in the Austrian capital. “This is a critical time but a positive outcome for everyone is possible,” Grossi tweeted Friday before leaving for Iran, where he is slated to meet with the head of the country’s Atomic Energy Organisation. The 2015 deal was aimed at guaranteeing that Tehran could not develop a nuclear weapon — something it has always denied wanting to do. The next few days are widely seen as a crunch point for negotiations. “We are close. E3 negotiators leaving Vienna briefly to update ministers on the state of play,” head of the British delegation Stephanie Al-Qaq said Friday, referring to negotiators from Britain, France and Germany. She added that they were “ready to return soon”. The three European countries, along with counterparts from China, Iran, and Russia, have been taking part in the latest round of talks in the Austrian capital since late November, with the United States participating indirectly. Grossi had vowed earlier this week that the IAEA would “never abandon” its attempts to get Iran to clarify the past presence of nuclear material at several undeclared sites. Iran has said the closure of the probe is necessary to clinch a deal. Grossi is expected to hold a press conference on his return to Vienna.