US seeking to ensure 'Turks don't slaughter the Kurds' in Syria

The United States is speaking to Turkey to ensure it does not "slaughter" Kurds in Syria as US troops leave, Secretary of State Mike Pompeo said on Thursday.

Pompeo referenced the growing fears for US-allied Kurdish fighters in northern Syria as he defended President Donald Trump's abrupt decision to withdraw from the war-battered country.

"The importance of ensuring that the Turks don't slaughter the Kurds, the protection of religious minorities there in Syria. All of those things are still part of the American mission set," Pompeo told Newsmax, a US news and opinion site popular with conservatives.

Defence Secretary Jim Mattis resigned over Trump's withdrawal order, angering the president who nonetheless later indicated he would slow down the planned exit.

Pompeo in the interview said that the withdrawal would go ahead but he would not give a more precise timeline so as not to tip off US adversaries.

Turkish President Recep Tayyip Erdogan has vowed to rid Syria of the Kurdish People's Protection Units (YPG), which he sees as linked to the Kurdish Workers' Party, or PKK, which has waged a bloody insurgency inside Turkey since 1984.

The Kurdish fighters formed the backbone of the Syrian Democratic Forces, who with Washington's backing have battled the Islamic State (IS) jihadist group and seized about a quarter of Syria.

Syria's government said on Wednesday that the YPG fighters have left Manbij, a key city seized from IS near the Turkish border, in light of the planned US pull-out.

Trump, who declared that US troops were no longer needed as IS was defeated, spoke to Erdogan before his troop decision. 

But Pompeo said the United States still had "real concerns" with Erdogan, including on detentions of US citizens.

"There are lots of places where we need to work with President Erdogan and the Turkish leadership to get good outcomes for the United States," Pompeo said.

National security adviser John Bolton and the US pointman on Syria, Jim Jeffrey, are both due to hold talks next week in Turkey. (AFP)