United States Treasury Secretary Steven Mnuchin said on Friday that US President Donald Trump had authorised the drafting of "very significant" new sanctions to target Turkey after it launched an offensive in northeast Syria.
In the days since President Recep Tayyip Erdogan spoke with Mr. Trump by telephone about pulling American troops out of Syria, several senior American diplomats have said that Mr. Trump made a crucial error by not threatening sanctions ahead of the withdrawal.
Al Jazeera's Sinem Koseoglu reports from Istanbul. A war monitor gave a death toll of more than 100 so far and the United Nations said 100,000 people had fled their homes.
Trump said after a Sunday telephone call with Erdogan that he was informed of the Turkish operation, and had ordered USA forces to withdraw from the target area.
"These are very powerful sanctions".
"The president is concerned about the ongoing military offensive and potential targeting of civilians, civilian infrastructure, ethnic or religious minorities - and also, the president wants to make very clear, it is imperative that Turkey not allow even a single ISIS fighter to escape", Mr. Mnuchin said.
Mnuchin stressed that the sanctions have not yet been activated, but that Trump has given the approval to issue them.
He said that Turkey's operations were defensive and legal under the charters of both the United Nations and North Atlantic Treaty Organisation, to which to which Turkey belongs.
"We are putting financial institutions on notice", Mnuchin said Friday in the White House briefing room.
The US this week moved two high-profile ISIL prisoners being held by the Syrian forces out of Syria. Although U.S. troops had no intention of firing on Turkey, its North Atlantic Treaty Organization ally, the Pentagon noted they had the right to defend themselves. He also pushed back against criticism that the USA troop pullback was a green light to Turkey, portraying it instead as a decision taken to protect his forces.
Milley said Turkey had been told of USA positions in Syria.
Turkey's Defence Ministry said it took all measures to ensure no USA base was damaged while it responded to harassment fire that originated near a US base in Syria.