The PKK terror group collects €25 million (over $28 million) annually in donations from across Europe, Germany's spy agency said in its report released on Tuesday.
The group, which is listed as a terrorist organisation by the European Union (EU), has collected more than €13 million (over $14 million) in Germany alone, between September 2015 and early 2016, according to the Federal Office for the Protection of the Constitution, or BfV.
"The PKK managed to double its revenues from donations in Germany within the last 10 years," the report said.
Germany outlawed the PKK in 1993, but Turkey authorities have been reluctant to take strong measures against the funding, propaganda and recruitment activities of the group, despite repeated warnings from Turkey.
Berlin's reluctance in combatting PKK activities in the country has been the source of major friction between Turkey and Germany.
BfV's annual report said the terrorist group had nearly 14,000 followers in Germany and had recently increased its recruitment activities, sending dozens to camps in northern Iraq.
It also warned that PKK followers may again employ violence in Germany.
"Though largely peaceful events prevail in Europe, violence remains an option of the PKK ideology," the report said.
"The PKK continues to be able and prepared, if necessary, to use violence in Germany at least in isolated cases or to tolerate acts of violence carried out by its young adherents."
The group -- listed as a terrorist organisation by Turkey, the U.S., and EU -- resumed its armed campaign against Turkey in July 2015 and since then has been responsible for the deaths of approximately 1,200 security personnel and civilians, including women and children.
