Open Society Foundations, the philanthropic group founded by George Soros, announced Monday that it would stop its operations in Turkey, where the organization and its founder have been assailed by an increasingly authoritarian government.

The organization, which promotes justice and human rights in more than 100 countries, said that it would close its office in Istanbul after it became the target of “baseless” accusations that made it impossible to work in the country.

The Turkish government has tried to link Open Society to the Gezi Park protests of 2013; the organization has denied any role and dismissed the allegation as unfounded. One of the organization’s board members, Osman Kavala, was arrested and has been in jail for over a year without being formally charged, the organization said.

“We are deeply dismayed and disappointed that the foundation had to close,” an Open Society spokeswoman, Laura Silber, said on Monday. But, she said, “it became completely untenable.”