ISTANBUL — Human rights defenders on Monday called the continued detention of Osman Kavala, a philanthropist who promoted reconciliation with Armenians and Kurds in Turkey, a “political decision” that seeks to instill fear among Turkey's civil society.

On Tuesday, Kavala, who turns 62 this week, will have spent 700 days in prison on charges he organized mass protests to save an Istanbul park in 2013 in a secret effort to topple the government. He and 15 others return to court next week and, if convicted, face life imprisonment without the possibility of parole in a case decried by the European Union as undermining human rights.

President Recep Tayyip Erdogan has accused Kavala of “financing the terrorists in the Gezi events” and of receiving support from the “famous Hungarian Jew Soros,” referring to the American billionaire George Soros, who has become a bogeyman in Turkey and in far-right circles in the United States and Europe for his support for democratic causes.

“There is great political influence on the case,” Murat Celikkan of the Truth Justice Memory Center told a news conference. “It is a political decision that Kavala is being kept [in prison]. … His continued detention is unlawful.”