Erdogan announced Wednesday that his forces would launch a new offensive against "separatist terrorist organization" in Kurd-controlled areas "within a few days."
The Pentagon shot back, warning Thursday that "unilateral military action into northeast Syria by any party, particularly as U.S. personnel may be present or in the vicinity, is of grave concern," and called such a move "unacceptable."
Erdogan then reportedly received a call from Trump himself, urging the Turkish leader not to go through with the campaign.
The Wall Street Journal cited two U.S. officials Friday as saying Trump asked Erdogan to call off his attacks, and a Turkish official was quoted as saying the two men then "agreed on the need for more effective coordination."
Agence France-Presse also cited a Turkish presidential source as saying the leaders "agreed to ensure more effective cooperation on the subject of Syria."
The U.S. and Turkey began their involvement in Syria as allies supporting a 2011 rebel and jihadi uprising against the government, but their interests have since diverged as Washington shied away from an increasingly Islamist insurgency to support the Syrian Democratic Forces.
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