Russian Tupolev Tu-22 long-range strategic bombers conduct an air strike at an unknown location in Syria, in this still image taken from video footage released by Russia's Defence Ministry on November 18, 2015.

MOSCOW, Dec. 3 (Xinhua) -- Russian strategic bombers continued to strike Islamic State (IS) terrorists in Syria on Sunday, the Russian Defense Ministry said in a statement.

Six Tu-22M3 long-range bombers took off from Russia and destroyed IS ammunition warehouses, equipment and strongholds in the southeast of Deir al-Zour province, it said.

The warplanes were covered by Russia's Su-30SM fighters from the Hmeymim airbase in Syria. After completing the mission, the bombers returned to their base airfields.

This was the sixth airstrike by Russian strategic bombers since Nov. 15 as Syrian government troops backed by the Russian air force are finishing expelling IS terrorists from the country.

Last month, Russian President Vladimir Putin said that Russian military operations against terrorists in Syria were coming to an end, with the focus shifting to a political process.

To that end, Russia, Iran and Turkey are preparing for a Syrian National Dialogue Congress to be held in Russia's Black Sea resort of Sochi.