A Turkish soldier was killed and three others were injured in an attack by PKK terrorists in southeastern Diyarbakır province, security sources said on Sunday.Soldiers were guarding the construction site of a hydroelectric dam in Diyarbakir's Kulp district when they came under rocket and gun attack, the sources added.The PKK, listed as a terrorist organization by the European Union and the United States, has been involved in a bloody campaign under the pretext of Kurdish self-rule in southeastern Turkey since 1980s, which saw tens of thousands of civilians, Turkish soldiers and policemen killed in the conflict. The group largely ceased its activities after the government launched the reconciliation process to end the PKK's campaign of terror two years ago.The Turkish Air Force has been carrying airstrikes against the PKK in northern Iraq and the ISIS militants in northern Syria.240 PKK terrorists have so far surrendered to Turkish Armed Forces since July 24. Meanwhile, the Turkish Armed Forces have neutralized 812 terrorists since the military operations which started on July 22.