At least 25 masked PKK supporters damaged cars and tried to force their way into a Turkish mosque in north-western Germany, leaving behind slogans of the PKK organization, Germany police said Friday.Police in Bielefeld detained one man after Thursday's attack.A nearby building thought to be used by the Turkish nationalist organization, the Grey Wolves (officially known as "Ülkü Ocakları" in Turkish), was covered with PKK slogans.Violence has escalated in Turkey since a ceasefire between the state and the PKK terrorist organization broke down in July. The Turkish air force has also attacked PKK targets in northern Iraq. The group is listed as a terrorist organization by the United States and the European Union.Within Germany's population of 81.1 million, the number of residents with Turkish nationality stood at more than 1.5 million at the end of last year, according to the German Statistics Office. Residents with a Turkish background were estimated at close to 2.9 million.