Turkish President Recep Tayyip Erdoğan says Turkey cannot make distinctions between terrorist organisations in reference to operations against YPG and DAESH.
The cross-border military operation launched by the Turkish Armed Forces and the US-led coalition in Syria's Jarabulus district will continue until the YPG moves to the east of Euphrates river, Turkish Prime Minister Binali Yıldırım said on Wednesday.
He said in an interview broadcast live on a Turkish news channel that Operation Euphrates Shield aims to clear the PYD's armed wing, the YPG, as well as DAESH from a particular zone along the Turkish border in northern Syria.
"The Syrian opposition [Free Syrian Army] are [now] settled in Jarabulus, and have started to control the villages and towns near the area. But the whole zone, including Jarabulus, needs to be cleared of the PYD and the YPG. There should be Syrians [living there]," he said.
The YPG outfit is known to be the Syrian branch of the outlawed PKK. Although the PKK is recognised as a terrorist organisation by Turkey, the US and the EU, Washington considers its Syrian branch the YPG to be an ally in the fight against DAESH.
Operation Euphrates Shield was launched on Wednesday with the aim of ridding Turkey's borders of terrorist groups, helping to enhance border security and supporting the territorial integrity of Syria.
A US defence official said both A-10 "Warthog" ground attack aircraft and F-16 fighter jets were carrying out strikes in support of the operation.
Turkish Armed Forces (TAF)-backed Free Syrian Army (FSA) forces later announced that they had gained full control of Jarabulus, after a 12-hour operation.
A commander with the FSA, who requested anonymity, told Reuters that most of the DAESH terrorists in Jarabulus had withdrawn, some of them surrendering.
"DAESH terrorists have withdrawn and are heading south toward the city of al Bab," the Failaq al Sham commander said.
Many of the FSA fighters were from Jarabulus itself and were jubilant over what they saw as a long overdue intervention.
A Turkish news agency reported that 46 DAESH terrorists were killed in the operation. Other reports said that only one FSA fighter was killed and 10 others wounded. No Turkish forces lost their lives.
US Vice President Joe Biden also flew into Turkey, a key NATO ally with the alliance's second biggest armed forces, on a pre-planned trip hours after the operation began.
Addressing a news conference with Turkish Prime Minister Binali Yıldırım, Biden said Washington had made clear to the YPG that they should return east of the Euphrates river again - a red line for Turkey.
"They cannot, will not, and under no circumstances get American support if they do not keep that commitment," he said.
Addressing a press conference with the US vice president, Turkish President Recep Tayyip Erdoğan said the most important issue in the region was the fight against terrorism.
"Whether [the fight is against] DAESH, the PKK, the YPG or FETO, [they are] all terrorists in our view," he said.
"Al-Nusrah, Al-Shabab whichever [organisation it] is, [they are] all terrorist organisations," he added. "We cannot make distinctions [such as] bad terrorists, good terrorists. Terrorists are terrorists."
In reference to the YPG, which is reportedly fighting DAESH in Syria, Erdoğan said: "One terrorist organisation fighting with another one does not justify it."
Since January, rocket attacks on the Turkish province of Kilis from DAESH-held territory in Syria have killed at least 21 people while terrorist attacks in Gaziantep blamed on DAESH include Saturday's suicide bombing of a wedding that killed 54 and a car bomb attack in May that martyred two police officers.
Turkey had vowed to "completely cleanse" DAESH militants from its border region after the Gaziantep bombing.