German Chancellor Angela Merkel visits Turkey on Thursday for the first time since July's failed coup, seeking to bolster a relationship frayed by differences over issues from the fight against terrorism to free speech.
Merkel is due to hold talks with President Tayyip Erdogan and Prime Minister Binali Yildirim during the one-day visit to Ankara, and is also expected to meet members of the main secularist and pro-Kurdish opposition parties, officials said.
Turkey's migration deal with Europe, cooperation in the fight against Islamic State in Syria, intelligence sharing and human rights are expected to be on the agenda.
But the two NATO allies have been at odds over Turkey's crackdown on dissidents after the failed July 15 coup, as well as Turkey's claims, which Berlin rejects, that Germany is harbouring Kurdish and far-leftist militants.
A row is also brewing over intelligence gathered by German Tornado fighter jets operating out of the Incirlik air base in southern Turkey.
Germany, concerned Turkey could use the high-resolution aerial imagery in its campaign against Kurdish militants, has ruled out giving Ankara unfiltered access to the data.
Germany has rejected suggestions it is harboring militants connected to the banned Kurdistan Workers Party (PKK), which has waged a three-decade insurgency in Turkey and is considered a terrorist group by the European Union and United States.
But Turkish Deputy Prime Minister Veysi Kaynak told the state-run Anadolu agency on Wednesday that Germany had "given shelter to terrorists even during Turkey's hour of trouble."
He said Berlin was also sheltering members of what Ankara calls the "Gulenist Terrorist Organization" (FETO), the network of U.S.-based cleric Fethullah Gulen, which Ankara blames for last July's coup bid. Gulen denies involvement.
"The most important actors of the coup attempt...are being hosted in Germany," Kaynak said.
German media reported on Saturday that around 40 mostly high-ranking Turkish soldiers who worked at NATO facilities in Germany had requested asylum.
Turkey's defence minister has urged Berlin to reject the applications and warned a failure to do so could damage relations. Berlin has said the applications will be considered on a case-by-case basis.
More than 100,000 people have been sacked or suspended from the police, military, civil service and private sector on suspicion of supporting Gulen since last July's failed coup. Some 40,000 people have been jailed pending trial.
The crackdown has worried rights groups and allies including Germany, who fear Erdogan is using the coup attempt as a pretext to curtail dissent. Turkey says the moves are necessary to protect democracy and root out supporters of the failed putsch.