Azerbaijan and Turkey have started a joint military exercise in Azerbaijan's exclave Nakhchivan, which borders Iran, on 5 October.

The exercise dubbed "Sarsilmaz Kardeslik-2021" (Unshakeable Brotherhood) "is a fitting response from Baku and Ankara to the large-scale exercise which Iran has been conducting on the border with Azerbaijan over the last few weeks."

The Turkish defence ministry spokesperson said on 3 October that the aim of the exercise was to improve "friendship, cooperation and coordination" between the Turkish and Azerbaijani land forces. Ankara will continue to stand by "our Azerbaijani brothers by all our means in their legitimate cause," she added. The exercise will end on 8 October.

The Azerbaijani defence ministry has been largely quiet about the drill. It reported on 1 October that Turkish Deputy Defence Minister Muhsin Dere visited Nakhchivan. The report mentioned the "successfully continuation" of the Unshakeable Brotherhood joint exercise.

Meanwhile, Azerbaijani President Ilham Aliyev inaugurated a new border troops military unit on the border with Iran on 4 October.

The new military unit is in the southern Jabrayil District which Baku regained during the Second Karabakh War of September-November 2020. The unit is armed with Harop and Kuzgun drones, anti-tank guided missiles, 120-mm and 82-mm mortars, anti-aircraft cannons, and other equipment.

Earlier, during his visit to Jabrayil, President Aliyev commented on the ongoing tension between Baku and Tehran. He dismissed Iranian statements about Israeli presence in Azerbaijan as groundless allegations and warned Tehran "not to poke its nose" into Baku's affairs.