Washington: Russian warplanes have carried out airstrikes to support Turkey's offensive in northern Syria against the Islamic State, an important evolution in a budding Russian-Turkish partnership. The deepening ties threaten to marginalise the United States in the struggle to shape Syria's ultimate fate.

The air missions, which took place for about a week near the strategically important town of Al Bab, represent the Kremlin's first use of its military might to help the Turks in their fight against the militant group. The Russians seized an opening to try to build a military relationship with Turkey, a NATO member, as the US has sought to keep the emphasis on taking Raqqa, the Islamic State's self-declared capital.

Turkey's President Recep Tayyip Erdogan, left, and Russian President Vladimir Putin. Credit:AP

The Russian bombing is a remarkable turnabout from November 2015, when a Turkish F-16 fighter jet shot down a Russian Su-24 attack plane that had violated Turkey's airspace.

Russia and Turkey had been involved in a joint effort to establish a cease-fire in Syria - one that does not involve the US. At the same time, ties between the US and Turkey have come under growing strain as the Turkish president, Recep Tayyip Erdogan, has become increasingly alarmed about the Kurdish forces known as the YPG. The US has aligned itself with those forces to combat the Islamic State in Syria and capture Raqqa.