Russian jets have twice entered Turkish airspace, according to NATO, which has disputed Russia's account of an accidental incursion during action in Syria.
Russian officials say Syrian President Bashar al-Assad is crucial to fighting the Islamic State, while President Obama has called on the embattled leader to step aside.
Estonia's new Russian-language channel, ETV+, launches Monday. It is one of many projects across Europe meant to counter the Kremlin's own media blitz.
Private donors underwrote the 10-year effort to replace an old mosque with a bold structure that incorporates Russian architectural details. Moscow may have as many as 2 million Muslim residents.
US officials have requested that Bulgaria and Greece close their airspace to Russian supply flights.