US President Donald Trump has authorised "very significant" new sanctions to target Turkey after it launched an offensive in northeast Syria, Treasury Secretary Steven Mnuchin says.
However Mnuchin said the US was not activating the sanctions at this time but would do so if necessary.
"We are putting financial institutions on notice that they should be careful and that there could be sanctions," Mnuchin said on Friday.
"These are very powerful sanctions. We hope we don't have to use them, but we can shut down the Turkish economy if we need to."
He said Trump was concerned about Turkey's potential targeting of civilians and wants to make clear that Turkey cannot "allow even a single ISIS fighter to escape".
The announcement came as Turkish President Tayyip Erdogan declared Turkey would not stop its operation against the Kurdish YPG militia in northern Syria.
"We will never stop this step we have taken against the PYD/YPG ... we will not stop it no matter what anyone says," Erdogan said.
"We're receiving threats from right and left, saying stop this progress."
Turkey intensified its air and artillery strikes in northeast Syria on Friday, escalating an offensive against Kurdish militia that has drawn warnings of humanitarian catastrophe.
Australian Associated Press
