The conflict over Nagorno-Karabakh, which lies within Azerbaijan, some 270 kilometers (170 miles) west of the capital Baku, first erupted in 1988 when it declared its independence from Azerbaijan, and moved to join Armenia.
Over 30,000 people were killed on both sides in fighting between 1988 and 1994, and over 100 died following a 1994 ceasefire.
Nagorno-Karabakh remains under Armenian military control, and tensions between Azerbaijan and Armenia have persisted as a result.
The meeting between Azerbaijan's FM Elmar Mamedyarov and Armenia's Vardan Oskaryan is scheduled for January 23 in Moscow.
Residents of Nagorno-Karabakh overwhelmingly voted in a referendum on the republic's Constitution last month to reaffirm the predominantly Armenian region's independence from Azerbaijan.
More than 100 international observers and journalists from Russia, France, the United States, Italy, Israel, Serbia and other countries monitored the referendum.
Azerbaijan dismissed the referendum as a farce.
The United States, the European Union and other international organizations, including the Organization for Security and Cooperation in Europe (OSCE), said no country will recognize the referendum's results.
The Azerbaijani leadership is determined to restore its control over the separatist region.
