Iran has reportedly signed a "secret" arms deal with Russia to acquire thousands of advanced shoulder-fired missiles to help boost its air defences.
The Financial Times reported that a $US589 million ($734 million) agreement was signed in Moscow in December, citing leaked Russian documents seen by the FT and several people familiar with the deal.
It said Russia would deliver 500 man-portable "Verba" launch units and 2,500 "9M336" missiles to Iran over three years.
The Verba has been described as one of Russia's most modern air defence systems, which would give Iran increased capabilities to target low-flying aircraft, helicopters, cruise missiles and drones.
The reports come as the US continues to build up its military presence in the Middle East.
President Donald Trump has been threatening Iran with US strikes if a deal is not struck on Tehran's nuclear capabilities.
What is the Verba missile system?
The Verba is a Man-Portable Air-Defence System designed and manufactured by Russian military company KBM.
The weapon is made up of two parts: the missiles and the launcher.
The launcher is shoulder-fired, designed to be operated by small mobile teams that can quickly create dispersed air defence coverage without relying on fixed radar systems.
The missile has the capability to destroy targets flying at altitudes between 10 metres and 4.5 kilometres, travelling at speeds of about 600 metres a second.
John Conway, defence analyst and managing director of consultants Felix Defence, said the Verba could be beneficial for Iran to help defend against strikes that use a range of low-altitude aircraft.
Helicopters, for example, played a key role in the recent US military operation to capture Venezuelan President Nicolás Maduro.
"You would think that these would be probably optimised around critical infrastructure, where you would have lots of them positioned," Mr Conway told the ABC.
"Or potentially geographic choke points where a raid could go down, like in a valley system."
A unique capability of the Verba is its ability to track targets by identifying the heat signature using multiple infrared and ultraviolet spectrums.
The three thermal trackers can detect heat emitted by jet engine exhaust or the sun-heated exterior of an aircraft.
Boosting defence capabilities
Under the deal between Iran and Russia, deliveries of the Verba systems are scheduled in three tranches, running from 2027 through 2029, according to the FT report.
It said Iran had requested the systems in July last year.
In June 2025, the US carried out strikes on Iran's three main nuclear sites as the country joined Israel's military campaign against Iran.
Last year's strikes exposed Iran's defence capabilities as "insufficient", Fabian Hinz, missiles technology expert at the International Institute for Strategic Studies, wrote.
"Despite substantial efforts in recent years to strengthen its air defences, Iran has always primarily relied on deterrence by punishment through the credible threat of significant retaliation," according to Mr Hinz's analysis.
Iran has Russian-supplied S-300 systems, which are its most advanced air defence capability.
The long-range surface-to-air missile systems can cost more than $US120 million a unit, depending on the configuration.
Israeli officials reportedly claimed to have damaged Iran's S-300s in October 2024 strikes.
"They [Iran] probably realised they needed something more at the lower end of the spectrum to attack lower flying aircraft such as drones, cruise missiles or decoys," Mr Conway said.
"These shoulder-portable systems will be probably good at targeting lower-end threats and leave the bigger systems to go after the bigger fighters and bombers."
Iran and Russia's strategic ties
Russia has a strategic partnership treaty with Iran, although it does not include a mutual defence clause.
Earlier in February, a Russian naval corvette conducted manoeuvres with the Iranian navy in the Gulf of Oman, according to Russia's Defence Ministry.
Iran reportedly received up to six Russian Mi-28 attack helicopters in January.
In late 2025, a report by Ukraine's United24 Media also claimed Iran was set to acquire 16 new Russian Su-35 fighter jets.
Russia has also benefited from the partnership.
Iran granted Moscow a licence to manufacture its own Shahed attack drones, which it uses in mass attacks against Ukraine.
Last week, Mr Trump indicated he would decide on whether to attack Iran in the next 10 to 15 days.
Iran has vowed to retaliate "ferociously", repeating warnings it could escalate into a regional conflict.
Stephan Fruehling from the ANU's Strategic and Defence Studies Centre does not believe the Verba systems will deter any future "high-level bombing campaign".
"Both the US and Israel have faced these kinds of systems for years," he told the ABC.
"I don't see that this would be a major obstacle or major shift in the regional balance or US or Israeli ability to operate against Iran."
ABC/Reuters