Fifty-six Kurdish mayors have gone on trial in Turkey, charged with aiding and abetting a terrorist organisation.
They were indicted after writing to the Danish Prime Minister Anders Fogh Rasmussen asking him not to close down Danish-based Kurdish Roj TV station.
The government in Ankara says the station is a mouthpiece for the outlawed Kurdistan Workers Party (PKK).
Mr Rasmussen has expressed his shock that such a trial could take place in a country seeking EU membership.
Forty-five of the mayors attended the opening hearing in Diyarbakir, the largest city in Turkey's Kurdish-dominated south-east.
I find it rather shocking... that because you write a letter to me, you are being accused of violating the law
Anders Fogh Rasmussen
They are charged by state prosecutors with "knowingly and willingly" helping Kurdish rebels.
In court on Tuesday, the mayors argued that their letter to the Danish prime minister contained no words of support for the PKK and that asking the Danes not to close down a television channel was within their right to free expression.
The mayors - all members of the pro-Kurdish Democratic Society Party - face up to 15 years in prison each if found guilty.
The trial has been adjourned for two months.
Mr Rasmussen expressed his outrage over the indictment of the mayors earlier this year:
"I find it rather shocking... that because you write a letter to me, you are being accused of violating the law," he told the Danish media in June.
"It is shocking that it can take place in a country which is seeking EU membership," Mr Rasmussen.
Despite strong pressure from Ankara to revoke Roj TV's licence, the Danish government has refused to do so, citing freedom of speech.
Turkey - as well as the EU and the US - views the PKK as a terrorist organisation.
The PKK implemented a five-year unilateral ceasefire after its leader Abdullah Ocalan was arrested in 1999, but resumed armed activities in 2004.
After Abdullah Ocalan's arrest it also dropped its demands for an independent Kurdish state, calling instead for Ankara to open a political dialogue, increase cultural rights for Kurds and release imprisoned PKK members.
Ankara has mostly ignored such calls, though it has allowed some broadcasts in Kurdish.