The decapitation of the Iranian ruling regime could potentially have a cascading impact nearly 2,500km north in Ukraine, where Russian ground troops have been bogged down in a grinding war of attrition for over four years.

Over the last six months, Moscow has been pressing home its advantage in the skies through an ever-evolving army of drones, mostly thanks to Iran. That could change somewhat, with the regime in Tehran having used up most of its drone arsenal in the fighting with Israel and the US, and could likely not be in a position to supply these unmanned aerial vehicles to Russia as before.

The constant use of large numbers of versions of the Shahed-type kamikaze drones by Russia has led to a rapid exhaustion of the air defence resources of the Ukrainians. As stated in numerous official statements, by the end of 2025, Ukraine’s air defence capabilities had been significantly depleted as it tried to counter the drone threat from the skies.

A central concern for Ukraine has been Russia’s increasing production of long-range attack drones that it has used in mass attacks to strike targets in Ukraine. While Tehran’s role in supplying Russia with hundreds of long-range, kamikaze-style drones is long known, what has gone largely unnoticed outside Ukraine is Iran’s central role in teaching Russia to produce these drones itself, according to Amy McAuliffe, Visiting Distinguished Professor of the Practice, University of Notre Dame.

The war in Iran now could potentially upend that supply-side support to the Russians, at least temporarily. The longer the war in Iran drags on, the higher the chances that support for Russia on drone supplies could be impacted.

The total number of Shahed-type Unmanned Aerial Vehicles (UAVs) launched by Russia in 2025 amounted to 54,538, including approximately 32,200 Shahed-type strike UAVs, according to official Ukrainian data quoted by Igor Anokhin of the Washington DC-based Institute for Science and International Security – a non-profit, non-partisan institution dedicated to informing the public about science and policy issues affecting international security.

Russia has been using the Shahed 131s and Shahed 136s versions of the Iranian drones to overwhelm Ukraine’s air defences. Since early this year, Moscow has been reported to have begun using a modified version of these drones – the new Shahed 101 suicide drone – in frontline areas with Ukraine, one that is a more compact and technologically advanced version of the more widely-used Shahed UAVs.

Despite the smaller size compared to the more widely used Shahed 131s and Shahed 136s, the 101 variant carries a fairly sizeable warhead, weighing up to 9kg, capable of causing significant damage to shelters, equipment and troop concentrations on the Ukrainian front line. In addition, the new version appeared to have an extended range of between 600 and 800 kilometres. This made the Shahed 101 an effective means of striking tactical and operational targets, even if the launch sites are located far away from the combat zone.

The UAV was reportedly equipped with a four-element antenna – the CRPA or controlled reception pattern antenna, which are active antenna designed to resist radio jamming – and provides better resistance to electronic warfare measures, making it more difficult to intercept and likely more accurate during strikes.

Multiple warfare experts have suggested that the Russians had received a fresh batch of these new-generation drones, and given the pace of Russia’s efforts to produce these drones domestically, it is likely that the Shahed 101 will soon begin to be assembled in Russia instead of being imported entirely from Iran. The Shahed 101, is becoming a logical part of Russia’s strategy to saturate the front line with cheap strike UAVs, against which Ukraine is forced to spend expensive air defence missiles or stretch its countermeasures system to its limit.

The emergence of the Shahed 101 also indicates that Iran and Russia continue to modernise the tactics of aerial terror, attempting to compensate for losses on the battlefield with the power and technological sophistication of Iranian strike UAVs.

In October 2025, the UN concluded that Russia’s use of short-range, unmanned aerial vehicles against civilians in southern Ukraine constituted a crime against humanity and a war crime. In early January, wreckage of a drone found in Ukraine pointed to these new high-speed models of drones being deployed by Russia in the conflict, prompting Ukrainian President Volodymyr Zelenskyy to air fears over failing to keep pace. “We produce (drones) at about 1,000 a day. We really produce them, but it’s not enough. It’s still not enough,” he told political business leaders at the World Economic Forum on January 22.

Ukrainian intelligence suggests that Moscow, too, will also soon be fabricating some 1,000 drone units a day, in large part thanks to the support and technical assistance of Iran, according to McAuliffe.

As an expert on weapons technology and former assistant director of the CIA for weapons and counterproliferation, McAuliffe has documented that she believes the use of Iranian technology has helped Russia develop a fleet of sophisticated drones that are capable of penetrating Ukrainian air defences and straining the country’s resolve. By doing so, Moscow is able to preserve more expensive missiles for long-range precision strikes.

Russia was initially unable to produce large numbers of kamikaze drones, and the country’s military seemingly did not, at first, understand the decisive role long-range strike drones could play. Instead, Moscow relied more on traditional battlefield weapons, such as missiles. It mainly thought of drones as useful in the roles of intelligence, reconnaissance and surveillance, etc.

Tehran, meanwhile, had the expertise Russia needed and also had a defence relationship with Russia. Moreover, faced with a cash-strapped economy due to yearslong economic sanctions, Iran needed funds.

NATO’s Defence College Outlook of August 2025 published an article titled ‘Two to tango: Russian-Iranian drone cooperation’, where Katie Fricke, Taylor Hankins and Victoria Jones specifically pointed to the problems with this collaboration between Russia and Iran. “It is important for NATO to understand the drone warfare dynamics shaped by the Russia-Iran partnership. Analysing their innovations and integration into military doctrines is crucial for anticipating threats and developing countermeasures. Iran and Russia are strengthening their partnership through collaboration on Unmanned Aerial Systems (UAS) development and deployment”.

Iran’s drone programme presents a multifaceted challenge to NATO, they noted. “The acquisition of Western technology through reverse engineering, coupled with Iran’s growing reputation as a drone supplier, enhances its military capabilities and global influence.”

Russia’s use of Iranian drones in Ukraine exposes vulnerabilities in NATO-provided defence systems and undermines efforts to protect member states and partner countries, they said, adding the proliferation of this technology to other state and non-state actors “complicates NATO’s defence strategies”.