A senior Iranian official has criticized the Kremlin for linking U.S. sanctions against Russia to Moscow's approval of any revised nuclear deal with Tehran.
Russian Foreign Minister Sergei Lavrov said on March 4 in connection with massive U.S. financial and other punitive sanctions over Russia's war in Ukraine that Moscow would insist on "written guarantees at the minimum level of [the U.S.] secretary of state" before backing a new nuclear deal with Iran.
The announcement came shortly after Tehran said it had agreed to a road map with the UN's nuclear watchdog to resolve issues holding up negotiations with world powers in Vienna aimed at restoring the stalled 2015 nuclear deal with Iran.
Russia's invasion of Ukraine, which entered its 10th day on March 4, has prompted international condemnation and the imposition of sanctions by the United States and other countries intended to push Moscow to end the war.
Lavrov said Moscow's guarantees from Washington should ensure "that the current [sanctions] process launched by the U.S. will not in any way harm our right to free, fully-fledged trade and economic and investment cooperation and military-technical cooperation with Iran."
A senior Iranian official, speaking to Reuters, said that Russian negotiators in Vienna had been demanding the guarantees from Washington in recent days.
"There is an understanding that by changing its position in Vienna talks Russia wants to secure its interests in other places," the Iranian official told Reuters from Iran. "This move is not constructive for Vienna nuclear talks."
A senior Western diplomat who spoke to The Wall Street Journal said the last-minute demand from Moscow could make it impossible to reach a deal in time.
Russia is one of the signatories of the original 2015 deal, which provided Tehran sanctions relief in exchange for curbs on its controversial nuclear program. The Joint Comprehensive Plan of Action (JCPOA), as the deal is officially known, was abandoned by the United States in 2018 and some of its measures subsequently violated by Tehran.
Talks to restore the deal have been ongoing in Vienna since April, and the negotiations mediated by France, Germany, the United Kingdom, Russia, and China are reportedly close to reaching an agreement.
On March 5, the visiting head of the UN's International Atomic Energy Agency (IAEA) nuclear watchdog warned in Tehran that outstanding issues still threatened a deal.
International Atomic Energy Agency (IAEA) Director-General Rafael Grossi emerged from meetings with Iranian officials on March 5 saying he had had a "very fruitful exchange" but that there were "still matters that need to be addressed" by Iran.
Grossi told a press conference it was "clear" that a number of crucial differences still need to be resolved "together."
He suggested joint work with Tehran to resolve the issues would continue for three or four months.
Iranian media quoted officials there as saying Tehran had agreed to "present documents to the IAEA to close remaining issues."
Grossi was scheduled to meet in Tehran with the head of Iran's Atomic Energy Organization, Mohammad Eslami, and later with Foreign Minister Hossein Amir-Abdollahian.
Eslami emerged from his meeting with Grossi saying he hoped Tehran's cooperation with the IAEA would not be "politicized."
The IAEA later issued a joint statement with Iran's Atomic Energy Organization that said the sides had agreed to strengthen cooperation and that the Iranian side would provide written explanations to its questions relating to three sites no later than March 20.
Grossi said before his trip that it is "a critical time but a positive outcome for everyone is possible."
A quarterly IAEA report saying Iran has sharply increased it stockpile of enriched uranium of a purity allowing its quick processing to create weapons has added urgency to the negotiations.
Russian envoy and talks mediator Mikhail Ulyanov tweeted on March 3 that negotiations were "almost over."
The next day, his French counterpart Philippe Errera urged a quick return to talks "because we are very, very close to an agreement."
Iran signed the JCPOA with the United States, Britain, France, German, Russia, and China, plus the European Union.
The United States is involved in the current negotiations indirectly, but earlier expressed interest in seeing the deal revived by February.