Fighting parties, described as separatists, in Nagorno-Karabakh and Azerbaijan announced, Wednesday, a ceasefire that will come into force tonight (9 pm GMT).
The ceasefire was considered the end of what Azerbaijan called an "anti-terror" operation launched just one day earlier by Azerbaijan's forces.
The neighboring rivals have been disputing for decades over Nagorno-Karabakh.
The chief of the region announced: "Through the mediation of the command of the Russian peacekeeping contingent stationed in Nagorno-Karabakh, an agreement was reached on the complete cessation of hostilities from 13:00 [0900 GMT] on 20 September, 2023."
The statement added that the separatist forces agreed to withdraw all heavy military equipment and weaponry from the territory of Nagorno-Karabakh.
The announcement also included that all Armenian armed forces would be drawn down from territory controlled by Russian peacekeepers.
However, Armenia previously denied the presence of any Armenian troops in the breakaway region.
The Russian forces deployed to the region as part of an earlier ceasefire agreement brokered between Armenia and Azerbaijan in 2020, ending six weeks of fighting.