By Ali Kucukgocmen
SILIVRI, Turkey (Reuters) - Prominent Turkish businessman Osman Kavala and 15 other civil society figures went on trial on Monday accused of trying to overthrow then-Prime Minister Tayyip Erdogan's government by organising nationwide protests six years ago.
The case began against a backdrop of concerns about growing authoritarianism in Turkey, where tens of thousands have been arrested in a crackdown on dissent since a failed military coup targeting Erdogan in 2016.
The Gezi demonstrations in the summer of 2013 started as a protest against the redevelopment of a park in Istanbul, a city with limited green space, and quickly spread across the country.
Erdogan at the time dismissed the idea that the protests were environmentally motivated, saying they aimed to topple his government.
Kavala launched his defence on Monday in the court in Silivri, a town west of Istanbul and the site of Turkey's largest prison, where he has been held on remand since 2017.
"The accusation for which I have been imprisoned for the past 20 months is based on a series of claims that have no factual basis and defy logic," Kavala told the court.
Outside the courthouse several hundred supporters of the defendants gathered with riot police watching nearby.
The indictment calls for life sentences without parole for the defendants, who are accused of attempting to overthrow the government and financing the protests among other charges.
Kavala is accused of spreading the protests through his organisation, Anadolu Kultur, which promotes culture and human rights. A second defendant, Yigit Aksakoglu, was jailed pending trial last November.
Erdogan, now Turkey's powerful executive president after constitutional changes, and his cabinet of the time are all plaintiffs in the case. The indictment names 746 people as injured parties in the nationwide protests, holding the defendants responsible for all injuries and damage to property.
Authorities acquitted several of the defendants in a 2015 case also related to Gezi protests. The indictment said the evidence for that case had been re-evaluated.
(Writing by Daren Butler; Editing by Dominic Evans and Mark Heinrich)