(Bloomberg) -- German Chancellor Angela Merkel told Turkish President Recep Tayyip Erdogan that she expects his country to react with “restraint and responsibility” following U.S. plans to pull troops out of Syria.

Merkel and Erdogan spoke by phone on Sunday and both emphasized the importance of the political process led by the United Nations to end conflict in Syria, according to a German government spokeswoman. The Chancellor also praised Turkey for taking in Syrian refugees, the spokeswoman said.

The U.S.-led forces fighting Islamic State in Syria partnered and armed Kurdish YPG fighters and President Donald Trump’s decision to exit the country has left those allies vulnerable to Turkey. Ankara says the group is an extension of the Kurdish PKK that it’s been fighting for more than three decades, and which is designated as a terrorist organization by Turkey, the European Union and the U.S.

The German and Turkish leaders discussed migrants moving toward Europe and the fight against terror, Turkey’s state-run Anadolu Agency reported, citing the presidency. They agreed to remain in coordination following the U.S. pullout and the implementation of an agreement reached at a summit in Istanbul, according to Anadolu.

Islamic State has been pushed back thanks to coordinated efforts, but the group is still a significant threat that warrants further attention, the German government spokeswoman said in an emailed statement in Berlin.

Russia and Turkey held talks on Saturday in Moscow on Syria as they move to fill the void left by the U.S. pullout. The two countries have a crucial role to play in resolving the Syrian conflict, President Vladimir Putin told Erdogan in a New Year’s message published by the Kremlin on Sunday.

--With assistance from Onur Ant.

To contact the reporter on this story: Nicholas Comfort in Frankfurt at ncomfort1@bloomberg.net

To contact the editors responsible for this story: Sree Vidya Bhaktavatsalam at sbhaktavatsa@bloomberg.net, Tony Halpin

©2018 Bloomberg L.P.