U.S. President Donald Trump on Monday demanded Turkey stop its military incursion in Syria and imposed new sanctions on the NATO ally as Trump scrambled to limit the damage from his much-criticized decision to clear U.S. troops from Turkey's path.
Vice President Mike Pence said Trump had told Turkish President Tayyip Erdogan in a phone call on Monday to agree to an immediate ceasefire.
He also said he would travel to the region soon to try to mediate the crisis.
Turkey launched a cross-border operation into northern Syria on Wednesday just days after Erdogan told Trump in a phone call that he planned to move ahead with a long-planned move against America's Kurdish allies in the region.
Trump abruptly announced a redeployment of 50 American troops from the conflict zone to get them out of harm's way, dismissing criticism that this would leave the Kurds open to attack.
This was widely seen as giving Erdogan a green light for his operation.
With lawmakers in the U.S. Congress moving to impose sanctions of their own, Trump issued an executive order authorizing sanctions against current and former officials of the Turkish government for contributing to Turkey's military operation in northern Syria.
In a statement, Trump said he had increased tariffs on imports of Turkish steel back up to 50 percent, six months after they were reduced, and would immediately stop negotiations on what he called a $100 billion trade deal with Turkey.