Turkey says Kurdish militants in Syria will be 'buried in ditches'

Turkey has said Kurdish militants in Syria will be "buried in ditches" when the time comes, after US President Donald Trump began a complete withdrawal of military forces from the country.

The Islamic State group has been "beaten" in Syria, US President Donald Trump said on Wednesday in announcing a stunning order to pull American ground forces from the war-ravaged nation.

The momentous decision to withdraw, which runs counter to long-established US policy for Syria and the region, blindsided lawmakers, the Pentagon and international allies alike.

Turkey and the United States have long had their relations strained by differences in Syria, where the US backs the Syrian Kurdish YPG against the Islamic State.

Turkey considers the YPG a terrorist group and an extension of the outlawed Kurdistan Workers Party (PKK).

"Now we have Manbij and the east of the Euphrates in front of us. We are working intensively on this subject," Turkish Defence Minister Hulusi Akar said during a visit to a Qatari-Turkish joint military base in Doha, Anadolu news agency reported on Thursday.

"Right now it is being said that some ditches, tunnels were dug in Manbij and to the east of the Euphrates. They can dig tunnels or ditches if they want, they can go underground if they want, when the time and place comes they will buried in the ditches they dug. No one should doubt this."

Earlier this week Turkish President Recep Tayyip Erdogan warned of an "imminent" offensive against Kurdish-controlled areas of northern Syria.

The US said any unilateral military action by Turkey would be "unacceptable".

Turkey has taken part in two major operations in northern Syria since Kurdish forces took control of border areas, but has not gone east of the river to avoid direct confrontation with US forces.

Operation Euphrates Shield in 2016 saw Turkish-backed rebels win back key towns and cities in northern Syria from IS, and limited the spread of SDF-controlled territories after they also took part in an offensive against the jihadi group.

An operation against the YPG in Afrin earlier this year also saw Turkish-backed rebels take hold of key border areas in north-west Syria.

Kurdish forces control around 30 percent of Syria's territory, mostly in the oil-rich eastern region