Updated

The European Union says it's worried about the rule of law in EU candidate country Turkey after the jailing of Amnesty International's chairman and Turkish Medical Association members there.

EU foreign policy chief Federica Mogherini and Enlargement Commissioner Johannes Hahn said Friday that the detentions are the latest "worrying developments undermining the rule of law and independence and impartiality of the judiciary in Turkey."

They warned that improvements in these areas "remain essential to the prospects of EU-Turkey relations."

Amnesty's Turkey chairman, Taner Kilic, was arrested again on Thursday after a prosecutor appealed another court's decision to free him pending a verdict in his trial on terror-related charges.

Turkey started its EU accession negotiations in 2005 but the talks are at a virtual standstill, with some countries opposing membership.