The parliament of Azerbaijan's breakaway Nagorno-Karabakh region elected leader Bako Sahakian for a third three-year term on July 19.
Speaking on the same day, Hikmat Haciyev, a spokesman for Azerbaijan's Foreign Ministry called the poll "yet another provocation by Armenia," and "a blatant violation of Azerbaijan’s constitution and of international law."
The ministry on July 17 had issued a statement condemning the upcoming poll as illegitimate.
Baku and Yerevan have been locked in a conflict over Nagorno-Karabakh for years.
Armenia-backed separatists seized control of the mainly ethnic-Armenian populated region during the early 1990s in a war that killed some 30,000 people.
Diplomatic efforts to resolve the conflict during the last 25 years have brought little progress.
The international community still considers it as part of Azerbaijan and no country has recognized its 1991 declaration of independence.
With reporting by AFP