Syrian airspace coordination dating to later years of the Obama administration.

RT, here. Apparently not fake news:

Russian Tu-95 bombers have struck Islamic State (IS, former ISIS/ISIL) targets in Syria's Raqqa region using X-101 cruise missiles, the Russian Defense Ministry said in a statement, adding that it informed the US about the operation.

[...]The ministry also said it notified Washington about the strikes in advance using the “de-confliction” hotline. In October 2015, Russia and the US agreed to a flight safety memorandum which regulates flight paths and to inform each other of an emergency situation in Syria establishing the hotline to avoid dangerous aerial incidents in Syrian airspace.

Colonel John Dorrian, the spokesman for Combined Joint Task Force, confirmed it received the notification via the hotline.