Obama wants to talk with Erdogan about events in Turkey after July's attempted coup, the military campaign against Islamic State, and how to promote stability in Syria, Deputy National Security Advisor Ben Rhodes told reporters.

The White House said it opposes Turkey's push into areas in northern Syria controlled by the Syrian Democratic Forces, or SDF, an opposition group the Obama administration supports, as it stands to erode the united front against Islamic State. The Obama-Erdogan meeting is scheduled for Sunday.

It was not certain whether Obama would hold a formal meeting with the Russian president during the G20 summit of the world's biggest economies, which runs Sept 4-5. But the two leaders often speak on the margins of such summits, Rhodes said.