Turkey and Russia have agreed on how they will monitor compliance with the Nagorno-Karabakh truce.
Turkish President Recep Tayyip Erdogan said on Wednesday that there would be a joint centre where the countries will work together.
There was heavy fighting at Nagorno-Karabakh for about a month and a half. The region has been ruled by Armenian separatists for decades, but is part of Azerbaijan, according to the international community.
That country is seen as the winner of the military conflict and is allowed to keep the areas it has conquered. This agreement is causing great unrest in Armenia.
Russia has already sent troops to the region to enforce agreements between Armenia and Azerbaijan. The first men have now arrived there. The Russian army is deployed for at least five years on the front line at Nagorno-Karabakh, where observation posts are being set up.
Russia and Turkey are seen as essential allies of the former Soviet states that have fought each other in recent weeks. Russia has good relations with Armenia and Turkey with Azerbaijan.