"In Vienna: now meeting on #Libya with [Government of National Accord Prime Minister Fayez] Serraj; tonight meeting #Armenia and #Azerbaijan Presidents; tomorrow Int Support Group for #Syria," Mogherini tweeted.
A Sputnik correspondent reported from Vienna earlier in the day that Armenian President Serzh Sargsyan had arrived in Vienna for joint talks on Nagorno-Karabakh.
The Nagorno-Karabakh conflict erupted in 1988, when the autonomous region populated by mostly Armenians sought to secede from the Azerbaijan Soviet Socialist Republic, before proclaiming independence after the collapse of the Soviet Union in 1991. The warring sides agreed to a cessation of hostilities in 1994.
The situation in the mountainous region deteriorated in April, with Yerevan and Baku accusing each other of provocations and attacks. On April 5, Azerbaijan and Armenia signed a ceasefire in Moscow under Russian mediation.
Reconciliation efforts have been carried out by the Organization for Security and Co-operation in Europe (OSCE) Minsk Group since 1992. Outside the three co-chairs, the group includes eight permanent members – Belarus, Germany, Italy, Sweden, Finland, and Turkey, as well as Armenia and Azerbaijan.
