Senior Russian missile and air-defense specialists traveled to Iran last year as the Islamic republic expanded its military cooperation with Moscow.
Reuters, which first reported the story, said seven Russian experts visited Iran on April 24 and September 17, 2024.
The visits came at a critical time for Iran, as it was embroiled in a conflict with archfoe Israel, with the two sides launching military attacks against one another in April and October.
Neither Iranian nor Russian officials have commented on the report and there is no formal explanation for the trips. Analysts say that while the visits are noteworthy, they are not surprising.
Iranian Chief of Staff of the Armed Forces General Mohammad Bagheri (right) meets with Russian Security Council Secretary Sergei Shoigu (left), in Tehran in August.
"There has been a two-way learning process in the Iran-Israel tit-for-tat, which also provided the Russians with data about air defenses," Nicole Grajewski, a fellow at the Carnegie Endowment for International Peace's Nuclear Policy Program, told RFE/RL.
In addition to domestically developed air-defense systems, Iran also uses Russian S-300 missile-defense systems whose delivery was completed in 2016.
In April 2024, satellite imagery showed that an S-300 radar had been damaged by a limited but precise Israeli strike, which came in retaliation for Iran launching a massive drone and missile attack weeks earlier.
SEE ALSO: Israel's Attack On Iran Has Left Tehran Offensively And Defensively WeakerThe failure of Russian-supplied air defenses to intercept the Israeli air strikes is another reason the Russian experts may have visited Iran, according to Farzin Nadimi, a senior fellow with the Washington Institute.
"One of the main purposes of the visits was to provide Iran with technical assistance to understand what exactly happened and how to defend against Israeli attacks," Nadimi told RFE/RL's Radio Farda.
"They were meant to study the data and improve the performance of air defenses against future attacks, which, as we saw, didn't work out," he added.
Israel last October retaliated against Iran's second and biggest-ever direct attack, targeting key military sites and degrading Tehran's air-defense and missile-production capabilities.
Would A US-Russia Deal Hurt Tehran-Moscow Ties?
The trips to Iran by Russian military experts represent the kind of perk that Tehran is loath to lose if Moscow and Washington reach an agreement requiring Russia to scale back its defense cooperation with the Islamic republic.
Since senior US and Russian officials met in Riyadh last month to normalize relations and end the war in Ukraine, there has been speculation that the Kremlin might give up Iran to get a better deal.
SEE ALSO: Iran Watches U.S.-Russia Talks With ApprehensionGrajewski argued that Iran and Russia do not have a strong economic relationship, so financially Tehran would not suffer much. But the impact could be felt elsewhere.
"If Russia does completely abandon Iran, Iran would primarily suffer the most in terms of improvements to its conventional military capabilities," she said. "The Russians have been crucial here both for the domestic production of Russian weapons and for the transfer of weaponry."
Iran has provided Russia with cheap but effective drones that have been used against Ukraine over the course of the war, and Western governments have accused Tehran of providing Moscow with ballistic missiles to aid in its 2022 full-scale invasion.
SEE ALSO: How Would Iran Benefit From Exporting Ballistic Missiles To Russia?The Washington Institute's Nadimi noted Russia's reliance on Iranian hardware was not due to a lack of technology but rather time, because Iranian drones are cost-effective and quick to produce.
Still, analysts said it was unlikely that any sort of agreement between the Kremlin and US President Donald Trump would result in a long-term change in Russia and Iran's defense cooperation.
"The key thing to remember is that the Russia-Iran relationship has many layers that may persist even with a US-Russia deal," Grajewski said.
She added that "military-to-military channels are so deeply embedded" that technology and knowledge transfer could continue even if only parts of the Russian government remain engaged with Iran.