Obama to meet Erdogan over Syria crisis: Official

The two presidents will meet on the sidelines of the Group of 20 summit in China on Sunday, said Ben Rhodes, the deputy US national security adviser.

"They will be discussing the counter-ISIL (Daesh) campaign and the fact that we need to stay united," Rhodes told reporters in Washington, DC, on Monday.

Turkey launched a bloody offensive in northern Syria last week and killed 25 Kurdish forces on Sunday, a day after a Turkish soldier died in a rocket attack allegedly by the Syrian Kurdish People's Protection Units (YPG).

Clashes between the Turkish forces and the YPG have been criticized by the Pentagon, which called them "unacceptable."

“We are calling on all armed actors to stand down immediately and take appropriate measures to de-conflict,” said Pentagon Press Secretary Peter Cook.

Meanwhile, US Secretary of Defense Ashton Carter called on Turkey to only focus on Daesh targets.

"We have called upon Turkey... to stay focused on the fight against ISIL and not to engage Syrian Defense Forces, and we've had a number of contacts over the last several days," Carter told reporters.

Ankara regards the YPG and YPD, the Syrian Democratic Union Party, as allies of the Kurdistan Workers’ Party (PKK), which has been fighting for an autonomous Kurdish region inside Turkey since the 1980s.

The US-allied YPG, which controls nearly the entire northern border with Turkey, has been fighting against Daesh. Conversely, Turkey is running a dual military campaign in Syria targeting both Daesh militants and the YPG.

Turkish Foreign Minister Mevlut Cavusoglu said Monday that Turkey’s military operation in northern Syria will continue until YPG withdraws to east of Euphrates.

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