Wiretapped telephone calls between a leading figure from the Islamic State and several members of the Turkish military reveal cooperation between ISIL and the Turkish military in letting smugglers cross the Turkey-Syria border.
The above link is only the most recent published story, this time from Turkish media, suggesting a close relationship between the Erdogan regime in Turkey, a NATO ally, and the Islamic State.
Not that long ago, shortly after the Turks shot down a Russian jet allegedly overflying Turkish airspace, the Russians presented taped phone calls indicating large scale financial deals between Erdogan, the Turkish leader's son, and significant authorities within the Islamic State for large scale oil transactions.
Below, a Russian news video exposing connections between Bilal Erdogan, the son of the Turkish president, and Islamic State leaders.
Lastly, linked here is a video released by a major Turkish News agency, Hurriyenet News, of the Turkish intelligence agency FSB, secretly sending large volumes of weapons and ammunition to Islamic State jihadis. The Journalists who wrote this story have been subsequently arrested.
That update is also in the above linked story.
One wonders at what point would NATO consider Turkey to actually be on the other side of this conflict.