The European Union risks losing credibility and contributing to political instability in the Balkans unless it draws the region’s states closer to their goal of EU membership, Carl Bildt, Sweden’s foreign minister, said on Sunday.

In an interview with the Financial Times, Mr Bildt, whose country holds the EU’s rotating presidency, warned that nationalists in the region might gain strength at the expense of pro-European political forces in several former Yugoslavian states if the prospect of joining the EU were to fade.