Russia's defence ministry said on Saturday Azeri armed forces had entered a zone that is the responsibility of Russian peacekeepers in the Nagorno-Karabakh region and had set up a surveillance post in violation of an agreement.
It said Azerbaijan had carried out four drone strikes in Nagorno-Karabakh. Moscow had called on Azerbaijan to pull out its troops, and was "applying efforts" to move forces to their initial positions, it added.
Azerbaijan's authorities were not immediately available for comment.
After a military conflict in September-November 2020, Azerbaijan emerged as the victor, recapturing territory it had lost in an earlier war between 1991 and 1994.
But many questions remain unresolved, including the legal status of Nagorno-Karabakh and the Armenians who live there.
Moscow deployed almost 2,000 peacekeepers to the region after the ceasefire, reaffirming its role as policeman and chief power broker in a volatile part of the former Soviet Union where Turkey also wields increasing influence thanks to its close alliance with Azerbaijan.
(Reporting by Reuters, Editing by Christina Fincher)
