U.S. Treasury Secretary Steven Mnuchin said Friday President Trump had given him and Secretary of State Mike Pompeo authority to impose sanctions on Turkey if it crosses certain lines in Syria.

Trump Sunday announced the U.S. would be pulling troops out of northern Syria that had kept Turkish and Kurdish forces fighting the Islamic State apart. Turkey long has considered the Kurdish forces a terrorist extension of Kurdish separatists within Turkey who have been fighting for an autonomous state.

 “These are very powerful sanctions and we hope we don’t have to use them,” Mnuchin said. “But we can shut down the Turkish economy if we have to.”Trump threatened earlier this week to do just that if Turkey fails to adhere to certain guidelines but did not enumerate what would trigger the sanctions.

Trump was to sign an executive order on the sanctions authority amid growing criticism of his decision on pulling out U.S. forces.

“The president is concerned about the ongoing military offensive and potential targeting of civilians, civilian infrastructure, ethnic and religious minorities, and the president wants to make very clear that it is imperative that Turkey not allow even a single ISIS fighter to escape,” Mnuchin told reporters at the White House.

The executive order will empower Treasury to sanction individuals and entities involved in human rights abuses or in undermining security in northern Syria.

Earlier, the Pentagon and Defense Secretary Mark Esper urged Turkish officials to halt the offensive in Syria or face “serious consequences.”

“Secretary Esper strongly encouraged Turkey to discontinue actions in northeastern Syria in order to increase the possibility that the United States, Turkey and our partners could find a common way to deescalate the situation before it becomes irreparable,” Defense Department spokesman Jonathan Rath Hoffman said in a statement.

Turkish President Recep Tayyip Erdogan swiftly responded, vowing that the assault "will not stop".

"Now there are threats coming from left and right, telling us to stop this," he said. "We will not step back."

Trump long has pledged to pull U.S. troops out of Syria and other war-torn areas of Syria, Iraq and Afghanistan, urging other countries in the region to pick up the slack. He said now that ISIS had been defeated, there was no reason for U.S. troops to remain.