International desk – Russia’s defence ministry says it has used a base in western Iran to carry out air strikes in Syria, according to BBC.
Tupolev-22M3 long-range bombers and Sukhoi-34 strike fighters took off from Hamedan on Tuesday, a statement said.
Targets were hit in Aleppo, Idlib and Deir al-Zour provinces, it added. Local groups said 27 civilians had died.
It is reportedly the first time Russia has struck targets inside Syria from a third country since it began a campaign to prop up Syria’s president Bashar al-Assad last year.
Iran is Assad’s main regional ally and has provided significant military and financial support since an uprising against him in 2011.
The US State Department said Russia’s use of an Iranian base was “unfortunate but not surprising”.
Asked about moves towards a possible agreement with Russia to co-operate in fighting so-called Islamic State (IS), a spokesman, Mark Toner, said closer Russian-Iranian ties would not necessarily preclude a deal.
But he added: “We’re not there yet.”
In recent months, senior Russian and Iranian officials have discussed boosting their military co-operation.
Last week, Russia asked Iran and Iraq to allow it cruise missiles to fly through their airspace for attacks on terrorist targets in Syria.
Russia has been operating jets and helicopters from bases in Syria for the past year, but this is the first time that Moscow has deployed aircraft to a third country in the region.
Reports indicate that up to six Tupolev Tu-22M3 bombers – known by the Nato codename of “Backfire” – are now operating from an air base in western Iran.
These planes – originally designed as a long-range strategic bomber – have already been engaged in the Syrian air campaign but operating from bases in southern Russia.
Placing them in Iran dramatically reduces the duration of their missions. The Russian defence ministry says that an unspecified number of Sukhoi-34 strike aircraft have also been sent to Iran.
The US has conducted hundreds of air strikes against IS and Jabhat Fateh al-Sham militants in Syria since September 2014, but it backs the rebellion.
Also on Tuesday, Human Rights Watch alleged that Russian and Syrian government aircraft had been using incendiary weapons in civilian areas in violation of international law – something Moscow has denied, BBC reports.