Germany expects Turkey to uphold an agreement with the European Union on curbing migration to the bloc following the departure of the minister who struck it, a German government spokesman said today.

Turkish Prime Minister Ahmet Davutoglu said yesterday he was stepping down as leader of the ruling AK Party and therefore as premier, raising questions about the migrant deal.

Davutoglu negotiated the terms with Brussels on stemming the flow of illegal migrants to Europe - an accord pushed by German Chancellor Angela Merkel who hopes it will shore up support for her conservatives ahead of a federal election next year.

German deputy government spokesman Georg Streiter said Merkel's government had worked well with Davutoglu and all Turkish officials, "and we expect this good and constructive cooperation to continue with a new Turkish prime minister."

"We will fulfill our commitments and expect that Turkey will also fulfill its commitments," Streiter told a regular government news conference, adding that the agreement was between states rather than between individuals.

Under the deal, Turkey agreed to help stem the flow of illegal migrants to Europe in return for accelerated EU accession talks, visa liberalisation, and financial aid.

It was already showing its first successes, Streiter said.

Asked whether Davutoglu's decision to step down was a bad sign, Streiter declined to give an assessment, saying: "It is a domestic political procedure within Turkey that I am not commenting on here."

Yesterday, politicians from Germany's ruling coalition voiced concern over Davutoglu's departure, saying it paved the way for President Tayipp Erdogan to rule unchecked.