US Vice President Joe Biden on Saturday said that the Kurdistan Workers Party (PKK) is a threat to Turkey like Islamic State, condemning the Kurdish militants as "a terror group plain and simple".

ISIS "is not the only existential threat to the people of Turkey, the PKK is equally a threat and we are aware of that.. it is a terror group plain and simple and what they continue to do is absolutely outrageous," Biden said after talks with Turkish Prime Minister Ahmet Davutoglu in Istanbul.