Chechen Muslims.
The Chechens were simply anti-Soviet Union before they were Islamic Jihadi. Chechnya sides with Hitler in WW II. The Islamists started moving to Chechnya in big numbers during the nineties, in support of the Chechen war against Russia, but the real reason was to break the line of demarcation that separated the Muslim Caucasus from Europe and Russia. The tribal fighting in the area actually worked to protect Europe and the Soviet Union from a Jihadi invasion.