The landlocked mountainous region of Nagorno-Karabakh is the subject of an unresolved dispute between Azerbaijan and its ethnic Armenian majority, backed by neighbouring Armenia.

In 1988, Azerbaijani troops and Armenian secessionists began a war which left the de facto independent state in the hands of ethnic Armenians when a truce was signed in 1994. During the fighting, more than one million fled their homes, the ethnic Azeri population fled Karabakh and Armenia while ethnic Armenians fled the rest of Azerbaijan.

Neither group has been able to return home since the end of the war. Significant progress was reported at talks between the leaders in May and November 2009, but progress stalled, and since then there have been a number of serious ceasefire violations.