In a move underscoring Moscow’s increasingly close ties with Tehran, long-range Russian Tupolev-22M3 bombers and Sukhoi-34 fighter bombers used Iran’s Hamadan air base to strike a range of targets in Syria.
It was the first time Russia has used the territory of another nation, apart from Syria itself, to launch such strikes since the Kremlin launched a bombing campaign to support Syrian president Bashar al-Assad in September last year.
It was also thought to be the first time that Iran has allowed a foreign power to use its territory for military operations since the 1979 Islamic revolution.
The Iranian deployment will boost Russia’s image as a central player in the Middle East and allow the Russian airforce to cut flight times and increase payloads.
The head of Iran’s National Security Council told state news agency IRNA as saying Tehran and Moscow were now sharing facilities to fight terrorism, calling their co-operation strategic.
Both countries back Mr Assad, and Russia, after a delay, has supplied Iran with its S-300 missile air defence system.
Relations between Tehran and Moscow have warm since Iran reached agreement last year with global powers to curb its nuclear programme in return for the lifting of UN, EU, and US financial sanctions.
Russian president Vladimir Putin visited in November and the two countries regularly discuss military planning for Syria, where Iran has provided ground forces that work with local allies while Russia provides air power.
The Russian defence ministry said its bombers had taken off from the Hamadan air base in north-west Iran.
To reach Syria, they would have had to use the air space of another neighbouring country, most probably Iraq.
The ministry said the strikes had targeted Islamic State, as well as militants previously known as the Nusra Front in the Aleppo, Idlib, and Deir al Zour provinces.
“As a result of the strikes five large arms depots were destroyed — a militant training camp, three command and control points, and a significant number of militants,” the ministry said in a statement.