A Turkish court acquitted leading businessman and rights defender Osman Kavala on Tuesday, February 18 in a highly controversial trial over the anti-government "Gezi Park" protests of 2013, AFP reports.

Kavala is chairman of the Anatolian Culture Foundation, which promotes human rights through art, including with neighboring Armenia, with which Turkey has no diplomatic ties.

The judge said there was "not enough concrete evidence" against Kavala and eight other suspects that appeared alongside him for the landmark verdict.

Kavala received loud cheers from the packed courtroom as he walked free.

"This is a trial that should have never happened in the first place," Emma Sinclair-Webb, of Human Rights Watch, said at the courthouse in Silivri, on the outskirts of Istanbul.

"This whole process has caused untold misery to those who were so wrongfully targeted, most of all Osman Kavala."

Kavala spent more than 800 days in pre-trial detention and became a symbol of what critics say is a crackdown on Turkey's civil society under President Recep Tayyip Erdogan in recent years.

Seven other defendants, who are fugitives, were not formally acquitted.

Prosecutors accused the group of 16 defendants, all leading civil society figures, of seeking to overthrow the government by orchestrating the mass protests that rocked the country in 2013.

The demonstrations began over plans to demolish Gezi Park -- one of the only green spaces in Istanbul's centre -- but quickly spiralled into broader protests against Erdogan, then prime minister.

Erdogan has called Kavala an agent of US financier George Soros, whose efforts to promote democracy around the world have made him a target for several authoritarian leaders.