The Latest on the developments in Syria's civil war after Russian warplanes took off on Tuesday from Iran to bomb Islamic State militants in Syria (all times local):

12:50 p.m.

In a first, Iran has allowed Russia to use one of its bases to stage and take off for attacks inside Syria — something unheard of in modern times in the Islamic Republic.

Iran's constitution, ratified after its 1979 Islamic Revolution, bans the establishment of any foreign military base in the country. However, nothing bars Iranian officials from allowing foreign countries to use an airfield.

In Tehran, the state-run IRNA news agency quoted Ali Shamkhani, the secretary of Iran's Supreme National Security Council, as saying on Tuesday that Tehran and Moscow have exchanged "capacity and possibilities" in the fight against the Islamic State group.

Shamkhahi says: "With constructive and extended cooperation between Iran, Russia and Syria and the resistance front (Hezbollah), the situation has become very tough for terrorists and the trend will continue until the complete destruction of them."

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11:50 a.m.

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.

Russia and Iran have been expanding their ties in the past months after most of the sanctions against Iran were lifted.