Separatists in Nagorno-Karabakh and Azerbaijan announced Wednesday they would cease hostilities, signalling the end of an "anti-terror" operation launched just one day earlier by Azerbaijan's forces in the breakaway region.

The historic rivals have been locked for decades in a dispute over the mountainous territory inside Azerbaijan that is inhabited mainly by ethnic Armenians and policed by separatists as well as Russian peacekeepers.

"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 region's self-proclaimed presidency said in a statement on social media.

The statement added that the separatist forces had agreed to disband entirely, and withdraw all heavy military equipment and weaponry from the territory of Nagorno-Karabakh.

The presidency's announcement also said that all Armenian armed forces would be drawn down from territory controlled by Russian peacekeepers. Armenia has said it has no troops deployed in the breakaway region.

The Russian forces deployed to the region as part of an earlier ceasefire agreement brokered directly between Armenia and Azerbaijan in 2020, ending six weeks of fighting.

The presidency's statement also said separatists had accepted a proposal from Azerbaijan for talks to integrate the disputed region into Azerbaijan.

"Issues raised by the Azerbaijani side on reintegration, ensuring the rights and security of the Armenians of Nagorno-Karabakh... will be discussed at a meeting between representatives of the local Armenian population and the central authorities of the Republic Azerbaijan," the statement said. 

"They will take place in the city of Yevlakh on September 21."