Turkey funded loads of Islamic schools in Xinjiang back when Erdogan was still on good terms with Gulen.
These were some of the indoctrination centers used to spread Islamism in China. They have since been shut down.
Erdogan still has a dream of a vast Pan-Turkish empire spread all over Central Asia.
I remember reading reports from Russia of Turkey flying militants into Chechnya and supplying them with weapons via helicopter drops back in the Chechen Wars. You had Turkish/US sponsored "East Turkestan" party militants in Chechnya. The Russians are in Syria because they know these dregs, which include the Chechen ISIS branch, would move closer to their border, probably into Chechnya again if they left them alone. Turkey already sent them as mercenaries via Azerbaijan to claw back Nagorno-Karabakh. They have also used them as muscle in the Libyan conflict. Previously they directly employed them against the Kurds in Northeast Syria. So any claims Turkey has no relations with these people, eh, who would believe them.
Turkey is playing a dangerous game on the Russian and Chinese backyards. So far both of these countries have cut Turkey a lot of slack because they see Turkey as an important player in the Eurasian space but they won't accept just anything to happen. Trying to destabilize Kazakhstan was a really low blow which I think pushed their relations almost to breaking point. Kazakhstan is a main hub in the Chinese OBOR project. The railroad route from China to Europe goes through it. The Central Asia–China gas pipeline which is used to power Southern China (Shanghai) with natural gas is fed though it.
