The eruption of hostilities between Israel and Iran—with the US joining the war on 22 June through its strikes on Iranian nuclear facilities—could have profound implications for the ongoing war in Ukraine, not least because of the disruption it is likely to cause to Tehran’s continued military support for Moscow.
From the outset of the Ukraine conflict in February 2002, Iran has played an increasingly vital role in providing much-needed military support for Russia in its campaign to control large tracts of Ukrainian territory.
Iranian drones and ballistic missiles, as well as other military hardware, have played a vital role in Moscow’s continuing war against Ukraine and have been used regularly to attack key Ukrainian targets, such as military positions and energy infrastructure.
Iran’s military involvement in the Ukraine conflict stems from the deepening ties Russian President Vladimir Putin has forged with Tehran since the conflict began. The first evidence that Iran was actively supporting Moscow in its military effort in Ukraine emerged in July 2022, when Russian President Vladimir Putin made one of his rare visits abroad to meet with Iranian Supreme Leader Ayatollah Ali Khamenei in Tehran.
Then-US National Security Advisor Jake Sullivan reported that the US had information indicating Tehran was “preparing to provide Russia with up to several hundred UAVs, on an expedited timeline”.
“Our information further indicates that Iran is preparing to train Russian forces to use these UAVs.”
While the Iran-Russia strategic partnership doesn't contain a mutual defence clause, it does state that if one country is attacked, the other must not assist the aggressor
Close alliance
Iran's close alliance with Moscow was reflected in comments made by Khamenei following his meeting with Putin, when he confirmed that the two countries had agreed to strengthen ties, and indicated that the West was ultimately to blame for the war in Ukraine.
"If you did not take the initiative, the other side would have caused the war with its own initiative," Khamenei told Putin.
The US has also accused Tehran of delivering close-range ballistic missiles to Russia for use against Ukraine, which Tehran has denied. The Kremlin has declined to confirm it has received Iranian missiles, but has acknowledged that its cooperation with Iran includes "the most sensitive areas".
Since Putin visited Tehran, relations between the two countries have deepened further, following Iranian President Masoud Pezeshkian's visit to Russia in January. This resulted in the Russian and Iranian leaders signing a 20-year strategic partnership between the two countries, which they said would take their relations to a new level across a host of areas, including trade, transport and energy.
Russian President Vladimir Putin and Iranian President Masoud Pezeshkian sign a strategic partnership treaty during a ceremony following their talks at the Kremlin in Moscow on January 17, 2025.
According to the terms of the treaty, which was signed just three days before US President Donald Trump returned to the White House to commence his second term, the two sides have agreed to combine resources against military threats and participate in joint exercises.
In return for Iran continuing to provide military support for Russia's war effort, Tehran was lobbying for Russia to provide a variety of sophisticated weaponry, such as long-range air defence systems and fighter jets, to defend itself against Israel.
Tehran has long hoped to obtain advanced Sukhoi Su-35 fighter jets from Russia to upgrade its ageing fleet, which has been hobbled by international sanctions, but it only received a few Yak-130 trainer jets in 2023.
Another important aspect of the deal for Iran was the prospect of securing further financial and defence commitments from Moscow. Putin has previously signed a similar deal with North Korea last year, further strengthening his alliance with Pyongyang.
Under that agreement, both sides committed to providing military assistance in the event that the other was invaded or attacked. North Korea has since sent thousands of soldiers to fight against Ukrainian troops in Russia's western Kursk region, hundreds of whom have been killed or wounded, according to South Korean, Ukrainian and Western intelligence.
And while the strategic partnership did not contain a mutual defence clause—unlike Russia's treaties with North Korea and Belarus—it does state that if one country is attacked, the other must not provide any military or other assistance to the aggressor.
This section of Russia's strategic partnership with Iran could have profound implications for Russian involvement in the conflict between Iran and Israel, and Putin has strong ties with both the Iranian and Israeli governments, and was in contact with both Iranian leaders and Israeli Prime Minister Benjamin Netanyahu shortly after hostilities commenced.
Russian President Vladimir Putin, right, prepares to greet Israeli Prime Minister Benjamin Netanyahu's wife Sara, unseen, before talks with Israeli Prime Minister Benjamin Netanyahu in the Kremlin in Moscow on Jan. 30, 2020.
Russian concerns
The intensity of the conflict between Israel and Iran, though, will have caused deep concern in Moscow, raising concerns that, with all the military resources of the Iranian government focused on defending it from Israel's deadly strikes, Tehran will no longer be in a strong position to continue supplying drones and other weaponry to support Moscow's ongoing military campaign in Ukraine.
Apart from targeting Iran's nuclear infrastructure, the Israeli military has also inflicted significant damage on the country's ability to maintain its production of missiles and drones.
A key element of Israel's Operation Rising Lion, as its military campaign against Iran is codenamed, since it began in mid-June, has been to neuter Iran's nuclear and long-range weapons capabilities.
To this end, Israeli forces began their campaign against Iran with an overnight attack on a wide array of Iranian targets, which included the use of drones and missiles launched by Israeli operatives located deep within Iran.
According to Israeli intelligence sources, Israeli forces deployed one-way attack drones and loitering anti-armour missiles to neutralise Iranian air defences and missile launchers in an attempt to limit Iran's ability to attack Israel.
The effectiveness of Israel's strategy was clearly evident from the early exchanges in the conflict, with reports that, while Iran had initially intended to fire 1,000 missiles at Israel in its opening salvo, it was only able to muster around 100.
A drone photo shows the damage over residential homes at the impact site following a missile attack from Iran on Israel, in Tel Aviv, Israel, June 16, 2025.
The fact that Iran has struggled to provide sufficient weaponry to defend its own interests will therefore raise concerns in Moscow that Tehran no longer has the ability to maintain military supplies for Russia's military campaign in Ukraine at the same level that was maintained prior to the deadly war breaking out between Iran and Israel.
Much to lose
The Israel-Iran conflict will undoubtedly be a significant concern for both Russia and China, another country that has established close ties with Tehran in recent years and relies heavily on Iran for its energy needs. Both countries have issued strong condemnations of Israel for launching its attack on Iran, and both have much to lose if Israel's offensive succeeds in reducing the Iranian government's ability to operate effectively.
Another issue that will concern the authorities in both Moscow and Beijing is that, as a result of the conflict, Iran will use the war as a pretext to withdraw from the Nuclear Non-proliferation Treaty, and race toward building a weapon – something Tehran has previously threatened.
Although both China and Russia have their own arsenals of nuclear weapons, neither is in favour of Tehran developing its own nuclear capabilities. If Tehran were to succeed in acquiring its own nuclear weapons arsenal, it would reduce the ability of both countries to restrain it.
Russia's President Vladimir Putin (R) shakes hands with Syria's President Bashar al-Assad during their meeting at the Kremlin in Moscow on July 24, 2024.
Losing another regional ally?
Another consideration that will concern the Kremlin's policymakers is the prospect of losing yet another key ally in the Middle East. The overthrow of the Assad regime in Damascus last year, which had previously been a close ally of Moscow, represented a major blow to the Kremlin's attempts to bolster its presence in the region. The loss of Iran, together with Syria, would seriously diminish Russia's regional.
Another important consequence of Iran's close ties with Moscow is that they have caused deep divisions within its government, with moderates claiming that the alliance has undermined Tehran's recent attempts to improve relations with the West.
The removal of Mohammad Javad Zarif, the former Iranian foreign minister who negotiated his country's controversial nuclear deal, from his position as vice-president in March was widely blamed on the deepening rift between moderates and hardliners over Iran's continued support for Russia.
The question of whether the alliance between Russia and Iran, which has hitherto been crucial to Moscow's war effort in Ukraine, is able to survive the current crisis will depend to a large extent on how long the conflict between Iran and Israel continues.
