One post on October 5th showed a picture of two men wearing the German gang’s jackets while climbing a hill with guns slung over their shoulders.
It said: “Our boys were in Kobane [Syria] today and told me today they were shot at but nothing happened. They are okay.”
Four days earlier, the Facebook user wrote: “While others blabber and blabber, our boys are at the front fighting Isis.” Alongside the caption he posted a picture showing a member of the club with Kurdish peshmerga fighters.
The group has also posted pictures praising fighters from Dutch biker gang “No Surrender” whose leader said on Tuesday it had three members fighting for the Kurds against Isis in Iraq.
The Cologne gang said it was also helping out with humanitarian aid.
One of the their Facebook group’s administrators uploaded a photo of a man whom he said was his “brother” and a Median Empire member with Yazidi Kurds, who have been persecuted by Isis, in what appeared to be a refugee camp.
Median Empire MC has previously fundraised in Germany for Kurds in the Middle East, but these are the first known fighters to have travelled from Germany to fight against Isis.
Around 400 jihadists are believed to have travelled from Germany to the Middle East to fight for Isis.
It raises the prospects of Germans fighting one another in Syria and Iraq and could inflame tensions on German streets where there have been clashes between Kurds and Islamists.
Security services have been trying to stop radicalized Muslims from travelling to the Middle East and Germany has outlawed Isis. But the stance of intelligence services on Germans fighting for the Kurds, who Germany is supporting with training and military equipment, is less clear.
A spokeswoman for Germany’s domestic intelligence service, the BfV, told The Local it had no official numbers on how many Germans had travelled to the Middle East to fight for the Kurds.
“This is a really new development, but we are monitoring it to see how things develop,” she said.
She said it was not illegal for Germans to travel to Syria, but it would be illegal for them to join outlawed Kurdish group the PKK, the Kurdish Workers’ Party, which is banned as a terrorist organization in Germany.
“We would have to prove what they are doing there,” the spokeswoman added.
The gang takes its name from the Median Empire which stretched across the Middle East in the 8th century BC. On their website they praise the empire’s warriors.
“The only difference today is that we are sitting on motorcycles instead of the backs of horses," it said.
Median Empire MC formed in Cologne in 2011, breaking away from another biker group called Mongols MC. The formation caused tension with the Hells Angels in the western German city.
It now has chapters in Karlsruhe, Cologne, Duisburg and Nuremberg as well as in Sweden and Russia.