MOSCOW/WASHINGTON, Aug. 17 (Xinhua) — Russia said Tuesday its bombers took off from an Iranian airbase to strike terrorist targets in Syria, in an unprecedented move that deepens its involvement in the Middle East and underscores Moscow's increasingly close ties with Tehran.

Russian defense ministry said that Tu-22M3 long-range bombers and Su-34 frontline bombers took off from Hamadan base in western Iran and "carried out a group air strike against the Islamic State (IS) and Nusra Front terrorist groups' targets in the provinces of Aleppo, Deir ez-Zor and Idlib."

Su-30cm and Su-35s fighters, based in Hmeimim air base in Syria, provided cover for the mission, according to the ministry.

Five large warehouses with weapons, ammunition, fuel and lubricants, three command posts and several training camps have been destroyed, and a significant number of terrorists have been killed in the campaign, the ministry added.

It was the first time Russia has used the territory of another nation, apart from Syria itself, to launch such strikes since Moscow launched a bombing campaign against IS targets inside Syria last September.

The Iranian deployment will boost Russia's image as a central player in the Middle East and allow the Russian air force to reduce flight times and increase bombing payloads.

Ali Shamkhani, secretary of Iran's Supreme National Security Council, said on Tuesday that Iran and Russia are "strategic" allies in fighting terrorism in Syria.

"Tehran-Moscow cooperation in the fight against terrorism in Syria is strategic and we exchange capacities and potentialities in this field,"   Shamkhani said.

Shamkhani also said that Iran will continue to provide military advice to countries plagued with terrorism, including Syria.

The Pentagon on Tuesday confirmed that the Russian military notified the U.S.-led coalition currently fighting the IS before Russian bombers carried out airstrikes in Syria from Iran.

"The Russians did notify the coalition as per the memorandum of understanding (MOU) for safety of flight," said Pentagon spokesman Christopher Garver, referring to the U.S.-Russian MOU signed last October to avoid an inadvertent clash in Syrian airspace during their own airstrikes against terrorist targets there.

"They (Russians) activated that system, as we have in the past. They informed us they were coming through and we ensured safety of flight as those bombers passed through the area and toward their target and then when they passed out again," Garver said at a press conference.

While he insisted that U.S.-led coalition operations in either Iraq or Syria were not impacted during the time, Garver refused to comment on whether U.S. aircraft had to be moved out of the path.

"We knew in time when they activate the safety of flight memorandum of understanding instructions. It's not a lot of time, but it's enough, and it was enough time to make sure that we could ensure safety of flight," said Garver.

Garver also declined to comment on whether the United States was aware of any major preparations on the Iranian base beforehand.