Angela Merkel has condemned the arrest of a German journalist in Turkey on charges of spreading “terrorist propaganda” and demanded that President Recep Tayyip Erdogan’s regime respect the freedom of the press.

Deniz Yücel, a correspondent for Welt newspaper who holds dual German and Turkish nationality, was arrested and formally charged on Monday after being held without charge for two weeks.

The charges appear to be related to a news report he wrote about a computer hacking attack against a minister who is also Mr Erdogan’s son-in-law, and an interview with a commander from the rebel Kurdistan Workers’ Party (PKK).

“This is unreasonably harsh, the more so because Deniz Yücel voluntarily came forward to the Turkish authorities and made himself available to the investigation,” Mrs Merkel said, adding that the arrest was “bitter and disappointing”.

Germany expects “the Turkish judiciary to respect the freedom of the press which is vital to every democratic society,” she warned.

Mr Yücel’s arrest comes amid a government crackdown on Turkey’s press that has seen more than 100 publications forced to close and been condemned around the world.

“These are dramatic times for Turkey. They are also difficult time for German-Turkish relations,” Sigmar Gabriel, the German foreign minister, said.