This change of heart came after Iran declared support for Turkey’s ambition to recreate an Islamic Caliphate via Ottoman revival. Russia and Ottoman have many territorial disputes. Russia can deal with a strong Iran aimed at Persian Gulf to keep US busy, but they cannot afford a reviving Turkey working with Iranian support on their border. Russia may change attitude of strong US presence in Middle East.
Actually Russia and Turkey have just announced a new strategic partnership.
http://en.rian.ru/world/20100510/158954539.html