Four-Day War

On April 1, 2016, Azerbaijani forces launched coordinated attacks along the line of contact in Artsakh (Nagorno Karabakh), using tanks, artillery, drones, and ground troops. The fighting lasted four days before a Russian-brokered ceasefire was reached in Moscow on April 5. Both sides claimed victory. Azerbaijan asserted it had captured around two thousand hectares, including the Lele Tepe heights in the southern sector; Armenian and Artsakh officials disputed the scale of the losses while acknowledging that some positions had changed hands. It was the most intense fighting since the 1994 ceasefire that had ended the first Nagorno-Karabakh war, and the first confirmed shift in the line of contact.

The conduct of the fighting drew international condemnation. Evidence emerged of Azerbaijani soldiers beheading Armenian soldiers and elderly civilians in captured villages, and of the use of cluster munitions in populated areas. Ilham Aliyev presented the offensive as a legitimate military operation to reclaim Azerbaijani territory; Armenia and Artsakh accused Baku of deliberate war crimes. The OSCE Minsk Group, the designated mediation framework for the Nagorno Karabakh conflict, was effectively sidelined during the ceasefire brokering, with Moscow handling the process bilaterally.

The April War unsettled Armenian domestic politics. The government of Serzh Sargsyan dismissed several senior military commanders in the aftermath. That summer, a group of armed men seized a Yerevan police station and took hostages, citing the territorial losses and demanding the release of opposition figures. The episode, carried out by a group called Sasna Tsrer, reflected a current of public anger over the perception that the military and political leadership had failed. A parliamentary investigation was launched in 2019. The war’s lessons about Azerbaijani military modernization, Turkish drone support, and the vulnerability of Armenian defensive positions were perceived to be be largely unaddressed, setting the conditions for the 44-Day War in September 2020.