In February 20, 1988, after a week of growing demonstrations in Stepanakert, capital of the Nagorno-Karabakh Autonomous Oblast (the Armenian majority area within Azerbaijan Soviet Socialist Republic), the Regional Soviet voted to secede and join with the Soviet Socialist Republic of Armenia. This local vote in a small, remote part of the Soviet Union made headlines around the world; it was an unprecedented defiance of republic and national authorities. On February 22, 1988, in what became known as the "Askeran clash", two Azerbaijanis were killed by Karabakh police. These deaths, announced on state radio, led to the Sumgait Pogrom. Between February 26 and March 1, the city of Sumgait (Azerbaijan) saw violent anti-Armenian rioting during which 32 people were killed. The authorities totally lost control and occupied the city with paratroopers and tanks; nearly all of the 14,000 Armenian residents of Sumgait fled.
When was the Askeran clash? (If the question is unanswerable, say "unanswerable")
February 22, 1988