• Iran has been one of Russia's few staunch allies throughout the war against Ukraine, but Tehran now faces the strain of indirectly fighting its nemesis Israel on two fronts.
• Iran could do with help from its powerful ally, Russia. The extent to which Moscow will — and can — help is uncertain.
• "If the Russians are going to bail on this, it's going to have consequences with regards not only to its relationship with the Iranians, but to any other partner, such as the Chinese," Chatham House's Bilal Y. Saab told CNBC.

Iran has been one of Russia's few staunch allies throughout the war against Ukraine, but Tehran now faces the strain of indirectly fighting its nemesis Israel on two fronts.

Under pressure — but still defiant — Iran could start looking to Russia for help, given its need for greater air defense capabilities and military intelligence to detect a highly-anticipated but yet-to-materialize direct Israeli attack on Iran, analysts told CNBC.

Russia is well-positioned to provide Tehran with such capabilities, but the extent to which it will assist the Islamic Republic remains uncertain.

"I fully expect that the Iranians have high expectations of the Russians to provide them with something," Bilal Y. Saab, associate fellow in the Middle East and North Africa Programme at think tank Chatham House, told CNBC Thursday, noting that reputation is of the utmost importance in international relations — even among authoritarian countries.

"So if the Russians are going to bail on this, it's going to have consequences with regards not only to its relationship with the Iranians, but to any other partner, such as the Chinese," he said.

"They've got to maintain some kind of reputation that they are good for it, and so I have medium-to-high expectations that they would actually provide them with what they need. Now, whether they provide them with everything they need, this is what nobody knows."

Russia is unlikely to offer military intervention against Israel on behalf of the Iranians, Saab said, given it is already "too bogged down in Ukraine."

"It's also too risky of a game to go against the United States over the Iranians ... so I think that [it's] more likely they would stay on the sidelines and try to help from as far away as possible," he said.

CNBC has contacted the Kremlin and Iranian foreign ministry for comment and is yet to receive a response.

'Strategic alliance'

Iran and Russia's "strategic alliance" has become far deeper since the latter invaded Ukraine in February 2022.

Tehran is one of only a handful of partners that a heavily sanctioned Moscow has been able to rely on to provide it military hardware.

Western officials have accused Iran of supplying Russia with hundreds of unmanned aerial vehicles (UAVs), and helping to build a drone factory in Russia. Kyiv says Moscow has used over 8,000 Iran-developed drones to attack it during the war so far.

More recently, and more concerning to Western officials, Iran has been accused of — and sanctioned for — sending ballistic missiles to Russia.

Arms transfers between the two allies have led the U.S. to describe Iran as Russia's "top military backer," although both countries deny drone and missile transfers have taken place. Tehran has conceded that it sent drones to Russia before the war began, however.

Russia also denies using drones to attack Ukrainian infrastructure, although there have been numerous instances of Iranian-made drones damaging Ukraine's power grid, military targets and civilian buildings during the conflict.

In the meantime, Tehran has turned to Russia to help build up its own military capabilities, looking to procure sophisticated Russia air defense systems and a variety of combat aircraft, according to reports, although the details surrounding the delivery of such hardware remain hazy.

"The provision of Iranian drones and, more recently, missiles to Russia for its campaign in Ukraine marked a significant evolution in the Russia-Iran relationship. In part, the war itself served as an accelerant to the already burgeoning Russia-Iran ties, propelling their cooperation to new heights," Karim Sadjadpour and Nicole Grajewski from the Carnegie Endowment for International Peace think tank noted in analysis earlier this month.

In return for Iran's support, Russia has bolstered Iran's military capabilities in several areas, they noted: "Iran has made notable progress in acquiring advanced conventional weaponry from Russia, allowing it to achieve some of its defense officials' long-standing goals. In November 2023, Tehran secured deals for Su-35 fighter jets, Yak-130 training aircraft, and Mi-28 attack helicopters, though only the Yak-130s have been delivered so far."

Russia has been offering Iran "an unprecedented level of military and technical support that is transforming their relationship into a full-fledged defense partnership," National Security Council Spokesperson John Kirby said in late 2022. "This partnership poses a threat, not just to Ukraine, but to Iran's neighbors in the region," he said at the time.

Fast forward to October 2024 and Russia's appetite to bolster Tehran's military capabilities might be waning as its war against Ukraine drags on, while Iran's ability to supply Russia with weaponry could now be limited.

Tehran is indirectly fighting its nemesis Israel on two fronts with its regional proxies, the militant groups Hamas and Hezbollah, coming under heavy and sustained Israeli attacks in the Gaza Strip and in Lebanon, respectively, and looking severely weakened after the deaths of the militant groups' leaders.

The factions, along with Iranian-backed Houthis in Yemen, make up what Tehran refers to as the "Axis of Resistance," which Iran backs in order to oppose Israeli and U.S. influence in the region. That shared antipathy toward the U.S. and desire to create a "new world order" are what largely binds Iran and Russia.

This week could bring more clarity on their deepening economic and strategic cooperation, when Russian President Vladimir Putin and his Iranian counterpart Masoud Pezeshkian meet on the sidelines of the BRICS summit in Russia.

Both countries have said they are close to signing a "strategic partnership agreement" — negotiations over which began in early 2022 — and this could be finalized at forum. It remains to be seen what the partnership will entail.

An alliance, with limits

Russia is likely watching the expansion of Israel's military action in the Gaza enclave and Lebanon carefully given its own military, economic and geopolitical interests in the Middle East.

It has, so far, maintained generally good relations in the region, including with arch rivals Iran and Israel, as well as deepening strategic ties with Syria, Saudi Arabia and the United Arab Emirates.

As such, the fighting between Israel and Iran's proxies could be starting to encroach on Russia's interests in the area.

The most recent example of this is Israel's Oct. 3 bombing of Iranian forces near Syria's Khmeimim Air Base, which has been operated by Russia since it propped up Syrian President Bashar al-Assad's government during the country's civil war a decade ago.

Analysts say it remains unclear what Russia would do to support Iran in the event of a wider and direct war between Iran and Israel, questioning the depth of the alliance and given the fact that Moscow is already enmeshed in the war in Ukraine, which is a massive draw on manpower and military resources.

"The escalating conflict between Israel and Iran is beginning to impact Russian interests in the Middle East, as well as threaten a whole range of Russian-Iranian projects," Nikita Smagin, an Iran expert with the Russian International Affairs Council, said in analysis Monday.

"Nevertheless, Moscow prefers to adapt to the evolving situation rather than to get directly involved. Russia cannot — and will not — save Iran in its confrontation with Israel and the United States," he noted.

Moscow's war in Ukraine means it has "no time" for another war, according to Smagin, who added that Russia would only be motivated to involve itself indirectly in the conflict with Israel if the end result were to weaken the U.S.

"Russia could seek to support Iran by supplying weapons to Iranian proxy forces, including Hezbollah and the Houthis," Smagin said. "However, for the Kremlin, that would be more logical if such deliveries were going to harm the United States, rather than Israel."