ISTANBUL: Micro-blogging site Twitter filed a lawsuit in an Ankara court on Thursday, seeking to annul a fine by the Turkish authorities for not removing content Turkey says is “terrorist propaganda”, a source familiar with the case told Reuters. A Turkish official said much of the material in question was related to the Kurdistan Workers Party (PKK) which Ankara deems as a terrorist organisation. A spokesperson for Twitter confirmed the company had taken legal action over the fine without providing further details. Ankara has taken a tough stance on social media under President Tayyip Erdogan and the ruling AK Party he founded. It has temporarily banned access to Twitter site several times in the past for failing to comply with requests to remove content. But the 150,000 lira ($50,000) fine, imposed by the BTK communications technologies authority, was the first of its kind by Turkish authorities on Twitter.