A leading figure in Istanbul politics has appeared in court over accusations she insulted President Erdogan and the Turkish state online.
Canan Kaftancioglu leads the Istanbul branch of the secular Republican People’s Party (CHP).
The opposition group claimed a stunning election victory over Turkey’s ruling AK party in Istanbul’s mayoral election last weekend.
Ms Kaftancioglu could face up to 17 years in prison.
Hundreds showed up to court to support Ms Kaftancioglu on Friday. Her trial has now been adjourned until 18 July.
The newly inaugurated Istanbul mayor, Ekrem Imamoglu, has alleged the charges against Ms Kaftancioglu amount to “political interference”.
“It is an attempt to restrict rights and freedoms. I will always stand by her,” he said.
Mr Imamoglu’s victory came after an earlier March result was annulled over alleged irregularities.
The CHP candidate dramatically increased his winning margin in the re-run.
What is she accused of?
Canan Kaftancioglu is standing trial over a number of tweets, reportedly dating back up to six years ago.
She is accused of “insulting” President Erdogan and the Turkish state in the posts, as well as allegedly “spreading terror propaganda”.
Reports say the alleged comments relate to 2013 anti-government protests and the outlawed Kurdistan Worker’s Party (PKK).
As leader of the CHP in Istanbul, Ms Kaftancioglu is seen as having played a significant role in Mr Imamoglu’s victory – which ended 25 years of AKP rule in the nation’s largest city.
The mayoral election was widely viewed as a referendum on President Erdogan’s rule. The leader, who has ruled since 2003 as both prime minister and president, had previously said himself that “whoever wins Istanbul, wins Turkey”.
The hashtag #TurkiyeSeninleCananBaskan (Turkey Stands With You, Chief Canan) trended online as she appeared in court.
The leftist Birgun newspaper quoted Ms Kaftancioglu as saying: “The light of hope in Istanbul has unsettled certain people” as she left the Caglayan courthouse.