Some doctors in the eastern province of Malatya testified to the police for using in a symposium poster the colours red, green and yellow, which are traditional Kurdish colours also used in the flag of the outlawed Kurdistan Workers Party (PKK), left-leaning daily Birgün reported on Thursday.

The doctors, who organised a liver tumour symposium, were invited by the police to testify over a liver image in the poster that was red, green, and yellow, Birgün said.

Investigations into people for things in red, green, and yellow has been a part of the Kurdish conflict in Turkey which has started more than three decades ago.

In 2017, Kadri Demir, a construction worker was accused of engaging in terror propaganda for a bird-shaped accessory in his car made of beads in red, green, and yellow as well as a scarf with the same colours. A Turkish court in the southeastern province of Diyarbakır later acquitted Demir.

In 2016, a man in the southeastern province of Şanlıurfa who painted his house in red, green, and yellow, were detained by the police and was released later on bail.

The three colours are also used during wedding ceremonies in the southeast and sometimes newly married couples are interrogated by the police for using red, green, yellow scarfs in their cars or wedding banquets.

Kurdish language and culture have been criminalised off and on since the earliest years of the Turkish Republic. In 2012, the ruling Justice and Development Party (AKP) began granting greater freedoms to the Kurdish culture.

But since the mid-2015 breakdown of the peace process between Turkey and the Kurdish militia the repression has returned. Countless Kurdish media organisations, associations, language schools, and cultural institutions have been shut down.