Turkish security forces called an end to operations in the town of Nusaybin near the Syrian border on Friday, security sources said, after nearly three months of often heavy clashes that left nearly 600 people dead.

Turkey's predominantly Kurdish southeast has been engulfed by the worst violence in two decades after the collapse of a ceasefire between the state and the outlawed Kurdistan Workers Party (PKK) in July.

While security forces completed Nusaybin operations, a round-the-clock curfew was still in place, the sources said. A total of 495 PKK militants and 70 Turkish soldiers have been killed since the operations in the town began on March 14, the local governor's office said in a statement.

Nusaybin, in Mardin province, is just across the border from Syria.

The PKK, which has taken up arms to seek autonomy for Turkey's Kurdish minority, is designated as a terrorist group by Turkey and its Western allies. It launched its insurgency in 1984 and more than 40,000 people have been killed in the conflict.