Mogherini said Sunday in her blog that she regretted that European leaders couldn't find an agreement despite "the extraordinary progress achieved by both countries and against the European Commission's advice."
French President Emmanuel Macron was the most vocal opponent of the membership talks during this week's European Council, arguing that enlargement procedures should first be improved before allowing new countries into the 28-member bloc.
Mogherini wrote: "it is much more than a lost opportunity: it is a historic mistake, which I hope can be amended as soon as possible."
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