Russia's air strikes in Syria will lead to a further escalation of the conflict, members of the US-led coalition against Daesh (IS) jihadists said Friday, calling on Moscow to immediately stop targeting Syrian opposition forces.

"These military actions constitute a further escalation and will only fuel more extremism and radicalisation," seven countries including Turkey, Saudi Arabia and the United States said in a statement published on the website of the Turkish foreign ministry.

"We call on the Russian Federation to immediately cease its attacks on the Syrian opposition and civilians," added the statement, which was also published on the German foreign ministry website.