The province, which was plunged into a conflict in the early 1990s, has been a bone of contention between Azerbaijan and Armenia ever since the violence.
The mediators represent the three countries that co-chair the Organization for Security and Cooperation in Europe (OSCE) Minsk Group, set up in 1992 to encourage a peaceful resolution of the conflict between the two former Soviet republics over Nagorny Karabakh.
The conflict over the province, which has a largely Armenian population, first erupted in 1988 when it declared its independence from Azerbaijan and its intention of joining Armenia.
Over 30,000 people were killed on both sides between 1988 and 1994, and more than 100 died following a 1994 ceasefire. Nagorny Karabakh remained in Armenian hands, but tensions between Azerbaijan and Armenia have persisted.
