Turkey has warned predominantly Kurdish Syrian forces of more strikes by Turkish forces unless they withdraw east of the River Euphrates immediately.
The foreign minister of Turkey Mevlut Cavusoglu discussed as Syrian opposition groups reported that Turkish -backed Syrian rebels have captured more towns and villages in northern Syria.
A move that was also targeted at discouraging additional progress by Kurdish, Turkish tanks rolled across the border last week to help Syrian rebels capture the town of Jarablus from the Islamic State group -led forces.
It leaves Washington in the tough spot of having to choose between two allies, and probably will divert resources from the fight against IS.
President Barack Obama will meet with the president of Turkey when he travels to Asia.
The White House said Mr Obama and Recep Tayyip Erdogan will meet on the sidelines of a major economic summit on Sunday. The two will discuss the recent assault of Turkey against the Islamic State group in Syria and growing tensions with Kurds in the area.
Both Turkey and the United States have ordered YPG, the Kurdish People’s Protection Units, or the main Kurdish fighting force, to withdraw to the east bank of the Euphrates.
“The YPG has to instantly cross east of the Euphrates River as they guaranteed the United States and as they announced they would,” said Mr Cavusoglu.
“If they don’t, they’ll be a target.”
The Kurdish-led force called the Syrian Democratic Forces crossed the Euphrates earlier this month and drove IS militants out of Manbij, a key supply hub south of Jarablus, after a 10-week campaign.
YPG leaders say they have, but the Syrian Democratic Forces are advised by their units, which is not clear if any stay west of the Euphrates.
Syrian opposition activists have said that at least 35 civilians were killed in northern Syria in the Turkish-led operation thus far.
Turkey denied any civilians have been strike.
A Turkish soldier was killed by a Kurdish rocket strike on Saturday, becoming the first such fatality in Turkey’s ground offensive.
The Observatory IS fighters on the western edge of Jarablus and also reported clashes.
An activist collective, the Local Coordination Committees, said the rebels had gained villages since on Sunday.