ANKARA, April 14 (Xinhuanet) -- Turkish security forces killed 21 militants of the outlawed Kurdish Workers' Party, or PKK, on Thursday in an operation launched in Turkey's southeastern region.

    Semi-official Anatolia News Agency reported that the members of the terrorist organization were killed in Dereler region between the cities of Siirt and Sirnak in southeastern Turkey, adding that operations are underway in the region.

    At the same day, the PKK militants killed a first lieutenant and two soldiers in a clash which erupted in Pervari Township in Siirt, the report said.

    Last week, Turkish security forces have launched the biggest operation against militants of the PKK in the last six years in southeastern border including cities of Sirnak and Hakkari.

    The PKK which aims at establishing an independent Kurdish state launched an armed campaign against the Turkish government in 1984.More than 30,000 people, mostly Kurds, have been killed in the violence in the mainly Kurdish southeast since then.

    Fighting has subdued significantly since PKK commander Abdullah Ocalan was captured in 1999.

    But the PKK called off a unilateral ceasefire in 2004, disrupting the fragile peace.

    The Turkish government refuses to negotiate with the PKK which it deems as a terrorist organization. Enditem