Turkey accused Kurdish militia in northern Syria of persecuting civilians on Tuesday and said it saw signs of "a kind of ethnic cleansing", drawing a parallel to the actions of Islamic State militants and forces loyal to President Bashar al-Assad.
Syrian Kurdish-led forces captured the town of Tel Abyad from IS on the Turkish border on Monday, driving the jihadists away in an advance backed by US-led air strikes.
Turkey is uncomfortable with the gains by Kurdish militia, which now controls almost half of the Syrian side of Turkey's 900km border, fearing it could inflame separatist sentiments among its own Kurdish minority.
"Daesh (Islamic State) attacks and kills those it captures. PYD/PKK (Kurdish militias) seize certain regions and force people living there to migrate," Mevlut Cavusoglu, a Turkish politician told state broadcaster TRT during a trip to Saudi Arabia.
"It doesn't matter who comes; the regime, Daesh, the PYD, they are all persecuting civilians."
He said the latest fighting had triggered a new influx of refugees to Turkey, already hosting 1.8 million Syrians, and that more than 23,000 people had crossed in the past week.
Deputy prime minister Bulent Arinc said late on Monday there were signs "pointing towards a kind of ethnic cleansing" by both Kurdish and Islamist groups as they fought in northern Syria.
"We see signs that work is being done on a formula to bring in other elements and combine cantons," Arinc told reporters, referring to two regions controlled by Kurdish forces in northern Syria.
On Sunday, the Kurdish YPG militia denied accusations of oppression or that a "racist war" was taking place. In a statement published online it urged civilians to return to cities controlled by Syrian Kurds, guaranteeing their safety.
President Tayyip Erdogan has voiced concerns about the latest YPG-led offensive, saying Kurds were taking over areas from which Arabs and Turkmen were being displaced. He has accused the west of backing what he called Kurdish terrorists and has said the outcome could eventually threaten Turkey's border.
The capture of Tel Abyad by the YPG and smaller Syrian rebel groups means the Syrian Kurds effectively control some 400km (250 miles) of the Syrian-Turkish border that has been a conduit for foreign fighters joining Islamic State.
The border area was quiet on Tuesday, with a small group of less than a hundred people crossing back into Syria after Islamic State fighters fled the town. Others were reluctant to return, saying they still feared the Islamic State militants.