Russia used Iran as a base from which to launch airstrikes against Syrian militants for the first time on Tuesday, widening its air campaign in Syria and deepening its involvement in the Middle East.
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 Assad last September.