Russia’s Defense Ministry says that Russian warplanes have taken off from a base in Iran to target Islamic State fighters in Syria.

Tuesday’s announcement marks a major development in the efforts against the Sunni militant group. Russia has never used the territory of another country in the Middle East — except Syria — for its operations inside Syria before this.

The ministry’s statement says Su-34 and Tu-22M3 bombers took off earlier in the day to target Islamic State and the Nusra Front militants in Aleppo, as well as in Deir el-Zor and Idlib, destroying five major ammunition depots, training camps and three command posts.

Moscow and Tehran signed a military agreement allowing Russian aircraft to station at Hamadan Airport in western Iran.

Tehran has agreed to share its military facilities and capacities with Moscow, confirming dedication to strategic cooperation in fighting against terrorism in Syria, Iran’s Secretary of Supreme National Security Council Ali Shamkhani told Islamic Republic News Agency (IRNA) in an exclusive interview on Tuesday.

The core benefit for the Russian Air Force is a drastic reduction in flying time to terrorist targets in Syria.

Russian long-range bombers delivered airstrikes in Syria from a base in Mozdok, Russia, and had to cover a distance of about 2,000km to get to Syrian airspace. Now that distance is reduced to some 700km, so time-sensitive airstrikes can be delivered immediately and more cheaply.