Arayik (Ara) Harutyunian has been sworn in as de facto president of Nagorno-Karabakh, the unrecognized breakaway Azerbaijani region.
The inauguration ceremony held on May 21 in the city of Shushi was attended by an Armenian delegation led by Prime Minister Nikol Pashinian.
Harutyunian, the former prime minister of the disputed region, won a runoff election on April 14.
Nagorno-Karabakh was seized by Armenian-backed separatists who declared independence amid a 1988-1994 conflict that killed at least 30,000 people and displaced hundreds of thousands.
Since a fragile, Russian-brokered truce in 1994, the region has been under the control of ethnic Armenian forces that Azerbaijan says include troops supplied by Armenia. The region's claim to independence has not been recognized by any country.
Since then, periodic skirmishes have taken place in the region.
Russia, the United States, and France are the co-chairs of the Minsk Group of the Organization for Security and Cooperation in Europe (OSCE), which acts as a mediator in resolving the crisis. The group has been struggling for years to mediate a solution.