Montenegro's Defence Minister Milica Pejanovic Durisic (L) shakes hands with NATO Secretary General Jens Stoltenberg (R) and Montenegro's Deputy Prime minister and minister of Foreign Affairs and European Integration during the second day of Foreign Affairs ministers Session with Montenegro meeting at the NATO headquarters in Brussels on December 2, 2015. NATO foreign ministers today invited Montenegro to join the US-led military alliance, a move Russia has repeatedly warned against as a threat to stability in the western Balkans. / AFP / JOHN THYS