Ankara, Feb 17 (IANS): Turkish President Recep Tayyip Erdogan vowed to expand Turkey's cross-border operations against the outlawed Kurdistan Workers' Party (PKK) after 13 Turks abducted by the group were killed in northern Iraq.

"We will expand our operations into areas where threats are still dense," Erdogan said at his party convention in the Black Sea province of Trabzon on Tuesday, Xinhua news agency reported.

Turkey will keep its presence in the areas that it cleared of the PKK out of its borders "as long as it's necessary," the president said.

"We will stay in these places which we will secure for as long as it takes so that we are not subjected to such an attack again," Erdogan said, adding that the Gara region in northern Iraq, where the Turkish military conducted a four-day operation, has now been secured.

Turkey on Sunday said 13 of its citizens abducted by the PKK were killed by the group in a cave in the Gara region during a recent cross-border operation.

The killings have strengthened Turkey's will to establish a safe zone along its border in northern Iraq to protect the country's frontiers, Erdogan stated.

Turkey launched the cross-border Operation Claw-Eagle 2 in the neighbouring country on February 10.

The PKK, listed as a terrorist organization by Turkey, the United States and the European Union, has been rebelling against the Turkish government for over 30 years, which has claimed the lives of more than 40,000 people.