The European Union has called on Turkey to amend a controversial article in its penal code in order to guarantee freedom of expression.
Journalists have raised concerns about aspects of the penal reforms
The move comes after a Turkish court upheld a prison sentence against an editor for insulting "Turkishness".
EU Enlargement Commissioner Olli Rehn said he was disappointed by the ruling.
It is the latest warning that Turkey's difficult progress towards the EU could be delayed by its failure to respect human rights, correspondents say.
"I am disappointed by this judgment, which limits the exercise of freedom of expression in Turkey," Mr Rehn said in a statement.
He said the ruling would set a binding precedent for other pending human rights cases.
"I would therefore urge the Turkish authorities to amend Article 301 and other vaguely formulated articles in order to guarantee freedom of expression in Turkey," the commissioner said.
The statement came a day after Turkey's high court a six-month prison sentence for Hrant Dink, the editor of bilingual Turkish and Armenian weekly, Agos.
The editor was convicted last year for an article criticising Article 301, which punishes the public denigration of Turkishness or state authorities.
This is the first final judgement based on the controversial article.
Mr Rehn is expected to issue a report on Turkey's progress by early November, but he has already warned that membership talks, which began last year, could soon grind to a halt.
There was international outcry when Orhan Pamuk, Turkey's best known novelist, was prosecuted under the article.
His offence, like that of Hrant Dink, was speaking about the mass killings of Armenians under the Ottoman Empire, which some European countries regard as genocide.
While the case against Mr Pamuk was dropped on a technicality, Hrant Dink could go to prison if he commits a similar offence in the next five years.
The human rights group Amnesty International says several other writers, publishers, artists and activists are charged with denigrating Turkishness.