Turkey's top court overturned terrorism-related convictions of the former local head of Amnesty International, Taner Kilic, and three other activists, the rights group said on Tuesday.
The Court of Cassation referred Kilic's case back to a first-instance court on the grounds of an "incomplete investigation", the group said.
The court was not immediately available for comment.
In 2020, Kilic, a former honorary chairman of Amnesty Turkey, was sentenced to more than six years in prison on charges of supporting U.S.-based cleric Fethullah Gulen, whom Ankara blames for orchestrating an attempted coup in 2016.
Three other rights activists were sentenced to two years and one month in jail for assisting a terrorist organisation. Those accused denied the charges.
At the time, the prosecution alleged the defendants who participated in a workshop on digital security on the island of Buyukada, near Istanbul, had come together for a secret meeting to organise an uprising and foment chaos.
Critics say that Turkey's courts muzzle free speech and political dissent under pressure from President Tayyip Erdogan, charges the government denies.
"Today's ruling brings to an end a travesty of justice of spectacular proportions," said Agnes Callamard, Amnesty International's Secretary General.
"While we are hugely relieved that the convictions have finally been quashed, the fact that the court has ruled that Taner's case requires further investigation is disappointing."
(Reporting by Daren Butler; Editing by Bill Berkrot)
