ISTANBUL (Reuters) - A Turkish court sentenced a German citizen to more than six years in jail on terrorism charges, state-owned Anadolu news agency said on Wednesday.

The detention and sentencing to jail of German citizens in Turkey under a crackdown following the 2016 coup attempt has been a major flashpoint in relations between the two NATO allies.

Saide Inac, a singer who also goes by the name Hozen Cane, was sentenced to six years and three months in jail for membership of an armed terrorist organization, Anadolu said.

An image of Inac alongside a senior member of the outlawed Kurdistan Workers’ Party (PKK) had circulated on Turkish media, following her detention. Inac said during her trial that she did not know who had shared the images, Anadolu said.

The news agency said Inac had denied being a member or a sympathizer of an illegal organization and had requested her acquittal.

She was detained at a police checkpoint in the northwestern province of Edirne after arriving in Turkey to help the pro-Kurdish Peoples’ Democratic Party’s (HDP) campaign ahead of June presidential and parliamentary elections, Anadolu said.

President Tayyip Erdogan and his AK Party say the HDP is an extension of the PKK, which Turkey, the United States and European Union consider a terrorist organization.

The HDP denies any direct links to the PKK and says it is being unfairly targeted by the government.

Relations between NATO allies Turkey and Germany soured after Berlin condemned Turkey’s arrests of some 50,000 people following the coup attempt, and the suspension or sacking of 150,000 others, including teachers, judges and soldiers.

Ties have improved in recent months, especially after Turkey released German-Turkish journalist Deniz Yucel in February and lifted a travel ban imposed on journalist Mesale Tolu following her release from prison in December after an 8-month detention.

Last month, a Turkish court also jailed a German citizen, publicly identified only as Patrick K., on charges of being a member of a terrorist organization.

Five German nationals are detained in Turkey for political reasons, a German foreign ministry spokesman said last month.