Turkey on Monday said it would continue targeting a Syrian Kurdish militia in Syria if it failed to fulfill promises to retreat east of the Euphrates River, accusing the group of ethnic cleansing.

Turkey on Monday said it would continue targeting a Syrian Kurdish militia in Syria if it failed to fulfill promises to retreat east of the Euphrates River, accusing the group of ethnic cleansing.

"The YPG (People's Protection Units) first of all... needs to cross east of the Euphrates as soon as possible. So long as they don't, they will be a target," said Foreign Minister Mevlut Cavusoglu.

"In the places where it has moved, the YPG forces everyone out -- including Kurds -- who do not think like it does and carries out ethnic cleansing," he added.

Ankara had said it had killed 25 Kurdish "terrorists" on Sunday as it pressed on with a two-pronged operation inside Syria which is said to be against the ISIL Takfiri insurgents  and the YPG.

The Britain-based Syrian Observatory for Human Rights said at least 40 civilians were killed in Turkish shelling and airstrikes, claims that were strongly rejected by Ankara.

"Allegations that... civilians were shot at or targeted do not reflect the truth," the office of the prime minister said, adding the army was taking "all necessary measures to prevent any harm to the civilian population".

The action against the YPG is hugely sensitive as the Kurdish group -- seen as a terror group by Ankara -- is an ally of Turkey's NATO ally, the United States, in the fight against ISIL in Syria.

Cavusoglu said the ethnic composition of the area around the city of Manbij west of the Euphrates -- captured by the YPG from ISIL earlier this month -- was largely Arab.

"Residents who had to leave the region (before fighting broke out) must be the ones who live there. But that is not the goal of the YPG," he said at a news conference alongside his Dutch counterpart Bert Koenders.

Cavusoglu also hailed what he said the success of the lightning operation by Turkish-backed fighters, who on Wednesday captured the town of Jarabulus from ISIL.

"The objective of this operation (Jarabulus) ... is to clear this region of the Daesh (ISIL) terrorist organization."

"As you see, even with a small force, the Daesh terrorist organization is leaving and running away from the regions under their control," he added.