°®Âþµº

The European Union's foreign policy chief on Saturday asked Turkey to forgo any unilateral military action in Syria, where Ankara has threatened a fresh offensive against a US-backed Kurdish militia.

"The statements of a possible Turkish military operation in northeast Syria are a source of concern," Federica Mogherini said in a statement.

"We share the goal of ending violence, defeating terrorism and promoting stability in Syria and the wider region," she said.

"We expect the Turkish authorities therefore to refrain from any unilateral action likely to undermine the efforts of the Counter-Daesh Coalition or to risk further instability in Syria," she added, using the Arabic acronym for the Islamic State group.

President Recep Tayyip Erdogan said Wednesday that Turkey will launch a new operation in Syria within days against Kurdish People's Protection Units (YPG) militia, which have Washington's support but which Ankara considers a terrorist group.

The Pentagon warned Wednesday that any unilateral military action in northern Syria would be "unacceptable".

Mogherini, calling Turkey "a critically important actor in this crisis and in the region", said that "as the fight against Daesh is entering its final stages, all parties must work towards the goal of ensuring its upcoming defeat".

Any Turkish military move against YPG would be complicated by the likelihood of Ankara's armies coming face to face with US troops deployed with the Kurdish militia.

Although Turkey and the US are NATO allies, their relationship has come under strain in recent years, notably as Washington's help for the Kurds triggered Ankara's anger.

On Friday, Erdogan appeared to stick to his guns, saying that Turkey was "determined to bring peace and security to areas east of the Euphrates" river in northern Syria.