Iran Foreign Ministry confirms receipt of S-300 long-range, surface-to-air missile as part of first batch of the deal.
Russia has been conducting long-range bombing missions in Syria against forces opposed to President Bashar al-Assad since the first days of its intervention in last September.
Flying from Russian territory, the majority of Moscow’s heavy bomber sorties have been undertaken by the Tu-22M3 Backfire aircraft. Alongside the powerful Su-34 Fullback, these Tu-22M3s are now conducting operations against targets in Syria from the Hamedan airbase in western Iran.
The Tu-22M, which was first introduced into Soviet service during the 1970s, is a swing-wing supersonic bomber capable of carrying around 20 metric tonnes of bombs or cruise missiles.
Today, it is predominantly used to drop large numbers of unguided “dumb bombs” from medium altitude on targets such as military camps and besieged cities.
Operationally, basing the Tu-22M in Iran will reduce by at least 60 percent the time needed to fly each combat mission over Syria, compared with flying from Russian bases.
While will this certainly increase Russia’s capability to generate Tu-22M sorties over Syria, it is likely to have only a relatively modest effect – sortie duration is far from the only factor limiting how many Tu-22M bombing missions Russia’s air force can generate.
The aircraft has traditionally not had good serviceability. In addition, the number of properly experienced and operational crews that Russia can field at any given time for its force of about 100 Tu-22Ms time is also limited due to funding challenges
Finally, it is not clear how much of the expensive infrastructure investment that Tu22Ms require has been made in Iran’s Hamedan by Russia.
If this deployment proves to be more of a political statement than a long-term operational basing move, then sortie rates for the bombers over Syria might actually be lower in the long term flying from Iran than Russia.
The Su-34, which is also reportedly flying from Hamedan, is Russia’s newest ground attack aircraft.
It has been flying from Latakia in Syria to attack forces opposed to Assad since the early stages of Russia’s intervention. Yet, it was part of the contingent of aircraft publicly withdrawn from operations there in March 2016.
Now that small numbers of these powerful attack aircraft are operating from Iran, they will actually be flying lower sortie rates than they had been able to from Latakia due to the greater transit distances involved.
However, part of the Russian decision to base Su-34s in Iran may be related to the destruction of four attack helicopters and 20 lorries loaded with missiles in eastern Homs in May by rocket fire from the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.
The Russian air force still only has relatively small numbers of Su-34s and their propaganda value as modern potent assets is high.
Thus, Moscow may be eager to keep them involved in their operations in Syria, without risking their destruction on the ground.
Overall then, in operational terms, the deployment of limited numbers of Tu-22M heavy bombers, and even smaller numbers of Su-34 fighter bombers, to Iran might have a limited effect in terms of increasing sortie rates to bomb targets in Syria.
However, the significantly more capable, versatile and precise Su-34s were previously based at Latakia in Syria and could generate even more sorties from there – so clearly that is not the main objective for them.
Equally, the Tu-22Ms require significant support infrastructure investment in Hamedan to deliver more bombs on Syria than flying from Russia in the medium-long term.
Even in such a case, these bombs will still be unguided and dropped “carpet-bombing” style from medium altitude on large targets, which limits their tactical utility and causes huge collateral damage and civilian casualties.
This move, therefore, is far more significant in geopolitical terms than operational ones, as it shows that Russia – like the US – can and will deploy strategic bombers to overseas bases for combat operations.
It also shows the Gulf Cooperation Countries nations that Iran – like the United Arab Emirates and Saudi Arabia – is prepared to host foreign strategic bombers for combat operations over other countries.
Justin Bronk is a Research Analyst in Military Sciences at the Royal United Services Institute.
The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial policy.