(Bloomberg) -- Israel’s trading of missile attacks with Iran this month may be on hiatus, yet the unprecedented direct clash between the two old foes has raised questions over the role played by Russia in the unfolding Middle East crisis. 

An operation believed to have been carried out by Israel on the Iranian city of Isfahan a week ago took out part of an air-defense system supplied by Moscow, according to US and Israeli reports. A day later, an Iranian official news agency trumpeted the imminent arrival of new fighter jets from Russia, later withdrawing the news without explanation. 

Russia is ready to expand its “mutually beneficial” military cooperation with Iran, Russian Defense Minister Sergei Shoigu said at a meeting with his Iranian counterpart Mohammad-Reza Ashtiani on Friday in the Kazakhstan capital of Astana.

The suggestion that Iran is sourcing weapons from Russia has raised concerns in Israel about the implications of expanding Moscow-Tehran defense ties — especially at a time when Israel and Iran appear closer than ever to all out war. Israel has its own backer in the US, and plans to use a recently-passed $26 billion aid package from Washington to strengthen its air-defense capabilities.

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Russia looks set to supply Iran with Sukhoi Su-35 fighter planes to modernize its decades-old air force as well as the sophisticated S-400 air defense system, said Shay Har-Zvi, a former acting director general in Israel’s Ministry of Strategic Affairs who remains close to the country’s security establishment. Moscow is also working with Iran on cyber warfare and sharing intelligence as well as helping it launch spy satellites, he said.

Russia is “an adversary for Israel — it supports the radical axis that is fighting against us,” said Har-Zvi, now a senior fellow at Reichman University near Tel Aviv. Moscow’s role will only grow in importance as Israel’s conflict with Iran and its various allied militant groups around the region intensifies, he added.

Supersonic Missiles

Israel managed to get past Iran’s air defenses on April 19 by firing supersonic air-to-surface missiles that damaged the Russian-made S-300 battery in an air base near Isfahan, according to Israeli state broadcaster Kan. The attack was a more limited response to Tehran’s massive missile and drone barrage on Israel six days earlier, allowing both sides to pause the tit-for-tat exchange without losing face. 

Russia has been relying on Iran for drones to support its invasion of Ukraine, giving the Islamic Republic leverage to bolster its armory with Russian help. The supplies of the two countries complement each other: Russia needs more drones and missiles, Iran lacks sophisticated air defense systems and fighter jets.

Reflecting the wider strategic shift, North Korea, another country that’s providing Russia with weapons to fight Ukraine, sent a delegation to Tehran this week.

“Russia and Iran are closer than ever thanks to the war in Ukraine,” said Major General (Reserve) Amos Gilead, a former top Israeli Defense Ministry official. “The Russians could now supply them with some very important technology that would represent a dramatic upgrade of Iranian capabilities,” he added.

Israel-Russia ties have been close in recent decades, forged by a personal relationship between Prime Minister Benjamin Netanyahu and President Vladimir Putin and long-standing security cooperation. But the two countries have been at increasing odds since Moscow invaded Ukraine in February 2022, with Israel’s close ties with the US making it impossible to stay neutral. That’s pushed Russia and Iran closer together.

Middle East Push

The Kremlin’s partnership with Iran is part of a broader push to counter the US and its allies in the Middle East, where Russia is seeking to step up its military presence, including with a naval base in Libya.

That’s provoked tensions over Syria, and Israel late last year stopped routinely informing Russia ahead of strikes in the war-torn country against Iran-backed militias. Israel regards its ability to hit targets in Syria as essential to obstruct Iranian weapons supplies to Lebanon’s Hezbollah, its most powerful enemy among Iran’s proxy groups. Russia, which is an ally of Syrian President Bashar al-Assad and has military bases in the country, maintains extensive air defense capabilities in Syria.

Read More: Israel’s Fight Spreads Into Syria, Poisons Ties With Russia

Russia took Tehran’s side after its April 13 missile barrage on Israel, with the Foreign Ministry describing the attack as an act of “self-defense” following deadly airstrikes on Iran’s diplomatic compound in Damascus two weeks earlier. Israel hasn’t confirmed or denied it was behind that assault, which killed high-ranking Iranian military leaders, in line with the country’s usual policy. 

Iran received the first delivery of Yak-130 combat trainer aircraft from Russia in September. They can be used to train pilots for the Su-35, and two months later the deputy Iranian defense minister said the arrangements for delivery of those fighter planes had been finalized. Iran’s current fleet of warplanes is outdated, including US F-14 aircraft that first entered service in the 1970s.

S-400 Query

Iran is also seeking the S-400 system, which can hit targets as far as 400 kilometers (240 miles) away and have some ability to counter stealth jets such as the US-made F-35 in Israel’s airforce, Bloomberg News reported last year. 

An Iranian official delegation visited a plant in the Urals city of Ekaterinburg that produces components for air defense systems including the S-400 in March 2023, according to a document posted online by a hacker group, Prana Network. The Washington Post first reported the Iranian visit. 

Russia’s cooperation with Iran has included the transfer of Western weapons captured in Ukraine such as anti-aircraft missiles, said Sima Shine, former head of research and analysis at Israeli intelligence agency Mossad and now head of the Iran program at the Institute for National Security Studies in Tel Aviv.

The two countries are likely to study the Israeli strike on the S-300 battery to understand how to improve air defenses, she said.

With Russian submarines also on the potential Iranian shopping-list, Moscow’s military alliance with Tehran is not only a worry for Israel, but for other US allies in the region like Saudi Arabia and the United Arab Emirates, said Yury Lyamin, a Russian expert on Iran.

“The only restraining factor now on Russia-Iran military cooperation may be Moscow’s desire not to cause a rift with Saudis and the Emiratis,” he said.

--With assistance from Marissa Newman, Galit Altstein and Thomas Hall.

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