The report also criticized Turkey's legal framework, the judiciary and frequent political intimidation that contribute to curbing freedom of expression. But the commission also welcomed Turkey's progress on some judicial reforms and the efforts to seek a lasting peace agreement with Kurdish rebels and strengthen the group's minority rights.
The European Union started negotiations with NATO member Turkey in 2005 despite skepticism among some of its member states to see a big Muslim nation join the predominantly Christian bloc of around 500 million people. Since then, Turkey's accession talks have made relatively little progress because of its territorial dispute with EU member Cyprus.
The next session of the EU talks will focus on regional policies, one of 35 chapters for aspiring members to address.
Turkish Deputy Prime Minister Bulent Arinc, responding to the report, warned that putting increased pressure on his country could undermine public support for EU membership.
He noted public backing had fallen from around 75 percent several years ago to "around 18 or 20 percent" now, blaming EU countries for the drop because they "put obstacle upon obstacle on Turkey ... and act irresponsibly."
Still, Arinc welcomed the EU's positive assessment of planned reforms including steps toward easing restrictions on the use of the Kurdish language.
EU officials say the bloc's enlargement policy coming with the promise of market access and financial support for aspiring members is a great success because it continues to help spread multi-party democracy and the rule of law. The EU has grown from a handful of members to 28 nations.
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Suzan Fraser contributed to this report from Ankara, Turkey.
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