Iran’s reported acquisition of Russian Su-35 fighter jets has revived a decades-old military and diplomatic contest in which Washington repeatedly intervened to prevent Tehran from obtaining advanced Russian combat aircraft. From the MiG-29 fighters of the early 1990s to the long-range MiG-31 interceptors, the United States has used diplomatic pressure, financial incentives and direct procurement to restrict Iran’s access to some of Moscow’s most sophisticated military aviation technology.
Iran’s Army spokesperson has now said that the country has completed the purchase of Russian Su-35 fighter jets and could receive them after the conflict with the United States ends. Although details of the agreement, including the number of aircraft, delivery schedule and payment arrangements, have not been officially disclosed, the announcement points to Tehran’s continuing efforts to modernise an ageing air force.
The Su-35, a highly manoeuvrable multirole fighter derived from the Su-27 family, represents a significant improvement over much of Iran’s existing combat aircraft inventory. Its advanced radar, electronic warfare capabilities, long-range weapons and powerful engines could strengthen Iran’s air-defence and air-combat capabilities.
However, Iran’s pursuit of advanced Russian fighters is not new. Its earlier attempts to acquire MiG-29s and MiG-31s demonstrate how Washington has repeatedly sought to prevent Russian military technology from reaching Tehran, particularly when such transfers were considered capable of changing the regional military balance.
Iran’s first major effort to acquire modern Russian combat aircraft began towards the end of the Cold War. In 1989, Tehran purchased approximately 18 MiG-29 fighters from the Soviet Union, with deliveries beginning in 1990. The acquisition was significant for an Iranian Air Force that had become increasingly dependent on ageing American-made aircraft following the 1979 Islamic Revolution and subsequent restrictions on military supplies from the West.
The MiG-29, known by its NATO reporting name Fulcrum, was among the Soviet Union’s most capable fourth-generation fighters. Designed primarily for air superiority, it combined high manoeuvrability, powerful engines and advanced short-range weapons.
One of its notable capabilities was the R-73, known by NATO as the AA-11 Archer, an infrared-guided air-to-air missile. When combined with a helmet-mounted sight, the weapon allowed pilots to engage targets at significant angles away from the aircraft’s forward direction. This gave the MiG-29 an important advantage in close-range aerial combat during an era when many Western fighters had more restrictive missile-targeting capabilities.
Iran subsequently received additional MiG-29s under unusual circumstances. During the 1991 Gulf War, Iraqi pilots flew several military aircraft into Iran to escape the US-led coalition’s air campaign. Tehran retained the aircraft, including MiG-29s, adding them to its own military inventory.
The collapse of the Soviet Union in December 1991 created another opportunity for Iran. Several former Soviet republics inherited advanced military equipment but lacked the financial resources to maintain their fleets. Moldova was among those countries, and its inventory included MiG-29 fighters inherited from the Soviet military.
Iran reportedly explored purchasing the Moldovan aircraft to expand its existing fleet. However, Washington viewed the possibility with considerable concern, particularly because some of the aircraft were MiG-29C variants that US officials considered capable of delivering nuclear weapons.
The United States was concerned that Iran could acquire an advanced delivery platform at a time when Washington was already questioning Tehran’s nuclear, chemical and biological weapons ambitions. Such an acquisition, American officials feared, could complicate regional security calculations and increase pressure on US allies, particularly Israel and the Gulf Arab states.
Rather than allow the aircraft to enter the international arms market, Washington decided to purchase them directly.
In October 1997, the United States finalised an agreement with Moldova to acquire 21 MiG-29 fighters. The package included 14 MiG-29Cs, six MiG-29As and one MiG-29B, as well as approximately 500 air-to-air missiles, spare parts and diagnostic equipment. The transaction was conducted under the Pentagon’s Cooperative Threat Reduction programme, originally established to secure and dismantle weapons and military equipment left behind after the Soviet collapse.
Then-US Defence Secretary William Cohen publicly explained the reasoning behind the purchase. He said Washington had credible information that several countries, including Iran, were attempting to acquire advanced Russian military equipment left available after the dissolution of the Soviet Union.
“These MiG aircraft were on their shopping list,” Cohen said.
He argued that preventing the aircraft from reaching countries seeking weapons of mass destruction was in the United States’ broader security interests.
The deal reportedly involved approximately $40 million in cash, alongside additional assistance to Moldova. The aircraft were dismantled and transported to Wright-Patterson Air Force Base in Ohio aboard US military transport aircraft.
For Iran, the American intervention represented a significant setback. The Moldovan aircraft could have provided Tehran with a relatively quick opportunity to increase the size and capabilities of its fighter fleet without waiting for a new production order from Russia.
The United States, meanwhile, gained something beyond preventing the transfer. By bringing the aircraft to American territory, it obtained an opportunity to examine Soviet fighter technology directly.
The MiG-29s were reassembled, inspected and studied by American specialists. Their components, radar systems, weapons and flight characteristics offered valuable intelligence about Soviet-designed combat aircraft. The experience could also support dissimilar air combat training, allowing American pilots to understand how to counter an aircraft they might encounter in a future conflict.
Israel was similarly interested in understanding the MiG-29’s capabilities. Reports at the time said the Israeli Air Force obtained access to three aircraft leased from an undisclosed Eastern European country for evaluation. Israeli assessments reportedly praised the fighter’s manoeuvrability and close-combat performance, although such evaluations did not necessarily mean it was superior to advanced Western fighters.
Although Washington considered the 1997 purchase a strategic success, the transaction later became a major political and legal controversy in Moldova.
Valeriu Pasat, who served as Moldova’s defence minister between 1997 and 1999, was arrested in March 2005 and accused of abusing his authority in connection with the sale of the 21 MiG-29s.
Prosecutors argued that the aircraft had been sold to the United States for approximately $40 million despite claims that Iran had been prepared to offer substantially more. They alleged that Moldova had suffered financial losses of approximately $55 million.
In January 2006, a court in Chisinau convicted Pasat and sentenced him to 10 years in prison. His lawyer, Gheorghe Amihalachioae, criticised the verdict as unfair and announced plans to appeal.
The case also attracted attention because former Moldovan president Petru Lucinschi testified that Washington had exerted pressure on Moldova to sell the aircraft to the United States rather than allow them to fall into Iranian hands.
Pasat spent more than two years in prison before an appeals court acquitted him of the MiG-29-related charges in 2007 and ordered his release under an amnesty. In July 2009, a further ruling cleared him of the remaining charges.
The episode demonstrated that the American effort to prevent Iran from acquiring advanced Soviet aircraft had consequences extending beyond the immediate military balance. It also exposed the diplomatic and political leverage Washington could exercise over countries seeking financial assistance and security cooperation.
The Moldovan MiG-29 episode was not the only occasion on which Iran attempted to acquire advanced Russian combat aircraft and encountered American opposition.
Tehran had also pursued the MiG-31 Foxhound, one of the Soviet Union’s most formidable interceptor aircraft. Unlike the relatively lightweight MiG-29, the MiG-31 was designed to intercept hostile aircraft and cruise missiles over enormous distances, particularly at high altitudes and speeds.
Developed as a successor to the MiG-25, the aircraft was built around long-range interception. Its powerful radar, high-speed performance and ability to carry long-range air-to-air missiles made it particularly suitable for defending large territories against strategic bombers and other high-value aerial targets.
Iran’s interest in the MiG-31 emerged while the Soviet Union was still intact. Reports indicated that Tehran had sought 24 interceptors as part of a much broader military procurement programme. Following the Soviet collapse, negotiations with Russia reportedly continued.
In July 1992, reports emerged of a proposed multibillion-dollar Russian arms package for Iran. The reported agreement included 24 MiG-31 interceptors, 48 MiG-29 fighters, 24 MiG-27 ground-attack aircraft and other advanced military equipment. Some accounts also included long-range Tu-22M bombers and airborne early-warning aircraft.
The scale of the proposed acquisition alarmed Washington. If completed, it would have represented a substantial expansion of Iran’s air-combat capabilities and potentially altered the military balance in the Persian Gulf.
Russia, struggling with severe economic difficulties following the dissolution of the Soviet Union, had strong financial incentives to sell military equipment abroad. Iran, meanwhile, was eager to rebuild its armed forces following the devastating Iran-Iraq War.
However, the proposed aircraft transfers became a major point of disagreement between Washington and Moscow. The United States opposed the supply of advanced combat aircraft to Iran and pressed Russian authorities to reconsider the proposed transactions.
Historical accounts indicate that the reported 1992 package was never implemented as originally envisaged. The scale and precise contractual status of the proposed MiG-31 sale remain disputed, with Russian officials disputing some reports about the agreement.
The dispute continued into the following years. In June 1995, Washington and Moscow reached an understanding under which Russia agreed not to conclude new conventional arms contracts with Iran and to complete existing commitments by the end of 1999. The arrangement, negotiated between then-US Vice President Al Gore and Russian Prime Minister Viktor Chernomyrdin, reflected Washington’s broader effort to limit the transfer of advanced Russian weapons to Tehran.
Russia subsequently announced in November 2000 that it no longer considered itself bound by the arrangement. This opened the door to renewed military cooperation between the two countries. In October 2001, Iran and Russia signed a military cooperation agreement that provided a framework for additional arms purchases, including discussions involving combat aircraft and air-defence systems. However, the agreement did not establish that the previously reported MiG-31 order would be delivered.
The repeated difficulties demonstrated a central problem for Iran: although Russia was willing to cooperate militarily, its arms relationship with Tehran was frequently influenced by Moscow’s wider diplomatic and economic calculations, particularly its relations with Washington.
Iran’s latest announcement about the Su-35 raises questions about whether the historical pattern of American intervention will repeat itself.
The Su-35 is considerably more advanced than the MiG-29s Iran acquired in the early 1990s. It features powerful engines, advanced radar and electronic warfare systems, a sophisticated flight-control system and the ability to carry a broad range of air-to-air and air-to-ground weapons.
For Iran, the acquisition would address a longstanding weakness in its military aviation capabilities. Much of its existing fighter inventory consists of aircraft purchased before the 1979 Islamic Revolution, including American F-14 Tomcats and F-4 Phantom II fighters, alongside Russian MiG-29s and other ageing platforms.
Years of international sanctions, limited access to Western spare parts and difficulties obtaining modern aircraft have complicated efforts to maintain and modernise the Iranian Air Force.
The Su-35 acquisition could therefore provide Tehran with an important technological improvement, although the aircraft’s actual contribution would depend on delivery numbers, weapons availability, maintenance infrastructure, pilot training and integration with Iran’s existing air-defence network.
According to the latest statement by Iranian Army spokesperson Brigadier General Mohammad Akraminia, the necessary contractual arrangements and pilot training have already been completed. He said the aircraft were originally expected to arrive before the conflict but would now be received after the war.
However, important details remain undisclosed. Neither the number of aircraft covered by the completed purchase nor the precise delivery schedule and financial terms have been officially established. Moscow has also not publicly confirmed the latest delivery arrangements.
The timing is particularly significant. Iran’s decision to delay receiving the aircraft suggests that the risks associated with bringing new fighters into an active conflict may have influenced its calculations. Newly delivered aircraft would require secure airbases, maintenance facilities and supporting infrastructure, all of which could become targets during military operations.
Washington and Israel will also be closely watching the development. Both countries have longstanding concerns about Iran’s military capabilities, particularly its ability to acquire advanced weapons systems from Russia.
Nevertheless, preventing the Su-35 transfer may prove more complicated than the earlier MiG-29 operation. Russia’s relationship with Iran has developed considerably, while Moscow’s confrontation with Western countries has created stronger incentives for military and strategic cooperation with Tehran.
The historical record nevertheless offers an important lesson. Iran has repeatedly attempted to obtain advanced Russian combat aircraft, but American diplomatic pressure and strategic intervention have sometimes prevented those ambitions from becoming reality.
The 1997 Moldovan purchase demonstrated that Washington was even prepared to buy the aircraft itself to keep them away from Iran. The MiG-31 negotiations showed how pressure on Moscow could undermine Tehran’s attempts to secure more sophisticated interceptors.
Now, with Iran claiming that its Su-35 purchase is complete, the question is whether Washington and Israel will attempt to influence the next stage of the deal or whether Russia will finally deliver the advanced fighters that Tehran has pursued for decades.
For Iran, the Su-35 represents more than another aircraft purchase. It is an opportunity to overcome a critical weakness in its air force. For Washington and its regional allies, it could mark another significant development in the changing military balance of the Middle East.
