Long standing tensions between Baku and Yerevan flared anew after Ilham Aliyev, the president of Azerbaijan, pardoned an axe murderer convicted of killing an Armenian army officer.
Last month, Ramil Safarov returned to Azerbaijan to a hero's welcome on returning home after serving eight years in prison in Hungary, where the murder took place.
Azerbaijan says condemnation over the pardon of Safarov distorts the facts behind a long-running territorial dispute.
Azerbaijan and Armenia have been fierce rivals since a war in 1988 over the disputed region of Nagorno Karabakh.
About 30,000 people were killed and a million, mostly Azerbaijanis, were driven from their homes.
Russia brokered a ceasefire in 1994 that left Nagorno Karabakh in Armenian hands, but the two sides have never signed a peace deal.
Al Jazeera's Robin Forestier-Walker reports from the Baku, Azerbaijan's capital.