Germany will support Ankara in its fight against extremists, Chancellor Angela Merkel told Turkish Prime Minister Ahmet Davutoglu in a phone call on Sunday, but she also urged the Nato partner to keep measures appropriate.

The phone call came after Kurdish militants killed two Turkish soldiers, apparently retaliating for Ankara's crackdown on the Kurdistan Workers Party (PKK), which was launched in tandem with strikes on Islamic State insurgents in Syria.

Davutoglu informed Merkel by phone about the actions of the Turkish government in the "fight against terrorism" following the attacks in Suruc and other attacks against Turkish security forces, a German government spokesman said.