The decades-old standoff between Armenian and Azerbaijani forces in Nagorno-Karabakh (also known as the Republic of Artsakh) escalated on 27 September, with both Baku and Yerevan accusing each other of sparking military hostilities.

Russia, France, the US, and other countries have urged the sides to the conflict to return to negotiations. The Turkish authorities, on the other hand, have backed Baku, saying that Ankara is ready to assist Azerbaijan "both in talks and in combat".

The Nagorno-Karabakh conflict began in 1991, with the predominantly Armenian-populated region proclaiming independence from Azerbaijan and confirming it during a referendum, announcing plans to join Armenia. After that, Baku and Yerevan waged a full-scale war for the area between 1992 and 1994, which resulted in the deaths of around 40,000 troops and civilians on both sides.

A ceasefire was mediated by the OSCE Minsk Group in 1994, but the conflict remained frozen, and the self-proclaimed Nagorno-Karabakh Republic still continues to be an unrecognised state.