Turkish officials say that as a result of counterterrorism operations on Turkish soil, DHKP-C -- often described as having a Marxist-Leninist philosophy -- became increasingly active among the Turkish diaspora in Europe.
The PKK, which has a Marxist-Leninist philosophy, at first carried out attacks in rural areas but moved into cities in the 1990s and expanded to include Turkish diplomatic interests in Western Europe, according to the U.S. State Department.