A man runs past a burning military vehicle aaA man runs past a burning military vehicle at a base controlled by rebel fighters from the Ahrar al-Sham Movement in the southern countryside of Idlib.t a base controlled by rebel fighters from the Ahrar al-Sham Movement, that was targeted by what activists said were Russian airstrikes at Hass ancient cemeteries in the southern countryside of Idlib, Syria October 1, 2015. REUTERS/Khalil Ashawi

Turkey and its partners in the U.S.-led coalition against ISIS called on Russia on Friday to cease its attacks on the Syrian opposition and focus on fighting Islamist militants, expressing “deep concern” over Moscow’s air strikes.

In a joint statement with the United States, Britain, France, Germany and Gulf Arab allies, Turkey said Russia’s actions constituted a “further escalation” of the conflict and would only fuel more extremism.

“We express our deep concern with regard to the Russian military build-up in Syria and especially the attacks by the Russian Air Force on Hama, Homs and Idlib since yesterday which led to civilian casualties and did not target Daesh,” it said.

Russian President Vladimir Putin said on Thursday assertions that civilians had been killed in Russian air strikes in Syria were an “information attack”.

Russia’s decision to join the war with air strikes on behalf of Syrian President Bashar al-Assad this week, and the increased military involvement of Iran, could mark a turning point in a conflict that has drawn in most of the world’s military powers.

Hundreds of Iranian troops have arrived in Syria to join a major ground offensive in support of Assad’s government, Lebanese sources said on Thursday, a sign the civil war is turning still more regional and global in scope.