vienna european union increasingly will consider western balkan state join bloc could help ensure peace region enrich eu bloc integration commissioner say willingness among eu member state address enlargement year ago johannes hahn tell austrian daily wiener zeitung interview publish tuesday albania macedonia montenegro serbia official candidates eu membership bosnia kosovo seek status eu see region important issue control immigration counter security threats range allege interference russia radical islam member state realize peace could achieve balkans perspective join eu vital hahn say western balkans 20 million people keen develop prosperity attractive market bloc hahn say add new member state burden enrichment commissioner say support idea multi speed europe would lead member state drift apart instead every effort make enable weak state catch strengthen european union say eu will consider new members balkans eu commissioner