Russian aircraft are free to use Iranian airspace as they attack Syrian targets, a top Iranian official said Thursday, according to Turkey's state-run Anadolu news agency. The statements come as Russia takes an increasingly active role in the Syrian civil war, including firing missiles from the Caspian Sea over Iranian territory. 

Iran Parliament Speaker Ali Larijani reportedly denounced Western military responses to the Syrian conflict in the interview, and praised the Russian response. He said Russian aircraft do not need prior approval to fly through Iranian airspace to conduct strikes on Islamic State group and Syrian targets.

“We do not need such an agreement, and Iran supports the Russian position on the fight against terrorism and will continue to assist Moscow,” Larijani said.

Russia has been conducting airstrikes in Syria since September, joining the United States and other Western nations in the effort. Moscow’s intentions appear to be quite different, however. Russian President Vladimir Putin and Syrian President Bashar Assad are allies, and the Syrian dictator thanked Putin for the airstrikes when they began. The U.S. and other Western powers have called on Assad to step down.

Iran and Russia are Assad's major foreign allies. Iran is a Shiite Muslim theocracy, and Assad is an Alawite, which is considered to be a sect of Shia Islam.

The open airspace is an important strategic consideration for Russia, especially after Turkey shot down a Russia jet for straying into its airspace last month. Without access to Iranian airspace it would be difficult for Russia to get its aircraft into Syria to conduct missions, except from ships in the Mediterranean.

Putin said Thursday that Turkey will regret shooting down the Russian jet “more than once.”