On Thursday (25 August), Azerbaijan took over the town of Lachin and two surrounding villages that had been under Armenian control for more than three decades. Under the provisions of the Armenia-Azerbaijan-Russia trilateral declaration of 10 November 2020 the handover was part of the arrangements that ended the 44 day Karabakh War.
Lachin, and the surrounding "Lachin Corridor" are considered of strategic importance since up to now they formed the only land connection between Armenia and the Armenian populated areas of Nagorno-Karabakh. A new road corridor has been constructed which bypasses the town of Lachin but serve the same purpose. The corridor, according to the trilateral declaration, will be monitored by Russian troops.
source: commonspace.eu