Erdogan vows to 'bring peace' to east of Euphrates

President Recep Tayyip Erdogan on Friday said Turkey was determined to bring peace to areas east of the Euphrates controlled by a Kurdish militia after he warned this week of a new operation in Syria.

"We are determined to bring peace and security to areas east of the Euphrates" River in northern Syria, Erdogan said during a speech in Istanbul.

"Turkey has lost enough time in terms of intervening to clean the terror swamp east of the Euphrates. We don't have the patience to wait one more day," he added.

The head of state on Wednesday said Turkey would launch an offensive against the People's Protection Units (YPG) militia within the "next few days" east of the river.

Ankara views the US-backed YPG as a "terrorist offshoot" of the Kurdistan Workers' Party (PKK), which is blacklisted as a terror group by Ankara and its Western allies.

But the YPG has spearheaded the United States' fight against the Islamic State extremist group under the banner of the Kurdish-led Syrian Democratic Forces (SDF) alliance.

The latest threats by Turkey are likely to cause tension with Washington after relations suffered in the past couple of years due to US support to the YPG.

Following Erdogan's operation warning, the Pentagon on Wednesday said any unilateral military action in northern Syria would be of "grave concern" and "unacceptable".

One of the main issues recently has been the setting up of US observation posts on the northeast Syrian border to prevent altercations between Turkish forces and the YPG.

Turkey had called on the US not to go ahead with the move last week. American forces are with the SDF east of the Euphrates as well as in the flashpoint city of Manbij, which is west of the river.

Following threats by Erdogan this year to attack YPG-held Manbij, the US and Turkey agreed a "roadmap" which would mean the YPG would leave Manbij and that NATO allies would work together to establish a local security structure and decide who will govern.

"Here is what we say: either you clean the city and (the YPG) leave, or we're going into Manbij as well," Erdogan said on Friday.