Concerns about Russia's role in the Vienna nuclear talks have opened a Pandora's box as Iran’s President Ebrahim Raisi plans to visit Moscow.

Diako Hosseini, a senior international relations advisor at the Center for Strategic Research under President Hassan Rouhani, said Russian negotiators had “cunningly” sidelined Enrique Mora, the senior European Union official chairing formal talks in Vienna between remaining signatories of the 2015 nuclear deal, the Joint Comprehensive Plan of Action.

In a Clubhouse session held by Khabar Online news website Sunday, Hosseini said that while Russia wanted the JCPOA restored, this was not based on Iran’s interests but because military confrontation between the United States and Iran, should the talks fail, would not be in Moscow’s interests.

In a commentary Tuesday in Shargh, a reformist newspaper, former diplomat Javid Ghorbanoghli accused Mikhail Ulyanov, the senior Russian negotiator in Vienna, of interfering in Iran's affairs for claiming Russia and China had convinced Iran to make concessions in the talks.

Ulyanov, who amid a general news blackout has been an active Tweeter, last week entered the debate as to whether current talks – which include formal and informal sessions within the JCPOA structure, and indirect contact with the US, which left the JCPOA in 2018 – are based more on drafts developed by June or on written proposals Iran submitted on November 29.

Speaking to Entekhab news website, Shahriyar Heydari, a member of the parliament's National Security and Foreign Policy Committee, also criticized Ulyanov, demanding an explanation from Ali Bagheri-Kani, Iran's top negotiator. "As far as we know, our negotiation team insists on the country's demands and has not changed its stances."

While Iran has since talks began back in April insisted that formal meetings remain within JCPOA structures and be committed to restoring the 2015 agreement, some in Tehran have argued for direct contacts with the US, as occurred for two years leading up to the JCPOA being signed in 2015.

Ulyanov and representatives of the western European JCPOA signatories – France, German and, the United Kingdom – all meet US officials. The Russian envoy has Tweeted photos of his meetings with White House officialRobert Malley, who leads Washington’s team in Vienna.

"The public's reading of this photo [of Ulyanov and Malley] … naturally implies a paternalistic Russian role in the Vienna talks," Ghorbanoghli said. "Moscow is (and was) concerned that the nuclear deal could be the starting point for improvement in Iran and US relations," Ghorbanoghli wrote, adding that in his view both Russia and Israel preferred Tehran-Washington antagonism to continue as it restricted Iran's options.

In an interview leaked in April, Mohammad Javad Zarif, then foreign minister and an architect of the JCPOA, criticized Russia’s role over the agreement and pointed to the absence of Russian Foreign Minister Sergei Lavrov in the group photo taken after the deal was signed.

Zarif, who was sanctioned by the US in 2019, said he resorted to "rude and non-diplomatic language" with Lavrov on some occasions.In August, conservative former lawmaker Ali Motahari said Russia was trying to sabotage the Vienna talks to prevent Iranian rapprochement with “the West.”