Although internationally recognised as belonging to Azerbaijan, the region of Nagorno-Karabakh is populated by ethnic Armenians, who fought a war of secession in the wake of the Soviet Union's collapse. The area is now an unrecognised but de facto independent republic with strong ties to the Republic of Armenia. Azerbaijan continues to claim the land and has complained that the ethnic Azerbaijani population that once lived there were ethnically cleansed in the war of the 1990s, with approximately one million Azerbaijanis forced to leave the area. Sporadic fighting has occasionally flared up since the end of hostilities in 1994, mostly in the form of artillery exchanges.
Last Sunday witnessed the outbreak of the fiercest fighting since the official end of the conflict — with the use of tanks, armoured vehicles and infantry formations, as well as heavy artillery bombardments.