October 26. According to APNews:
United States, Armenia and Azerbaijan issued a joint statement on the 25th announcing that the two countries agreed to a ceasefire at 8 am local time on the 26th. This is the third time the two sides have attempted to reach a ceasefire since the Naqqa conflict lasted for four weeks.
U.S. Secretary of State Pompeo stated on social networking sites that the U.S. coordinated “intensive negotiations” and that the foreign ministers of Armenia and Azerbaijan “have pledged to implement and abide by the ceasefire.”
A new round of conflict broke out in Armenia and Azerbaijan on September 27 over the Naka issue. On October 10, the foreign ministers of Russia, Azerbaijan, and Armenia issued a statement in Moscow saying that the two countries reached a ceasefire agreement in the Naka region and agreed to a ceasefire in the Naka region from 12:00 on the 10th local time.
On October 17, the two countries announced that they had reached an agreement to implement a humanitarian ceasefire in the Naka region, and agreed to implement a humanitarian ceasefire from 0:00 local time on the 18th. After the two ceasefire agreements came into effect, both sides accused the other of violating the agreement to launch attacks.
The Naka region is located in southwestern Azerbaijan, and its residents are mostly Armenians. After the disintegration of the Soviet Union, war broke out between Azerbaijan and Armenia over the ownership of the Naka region.
In 1994, the two sides reached an agreement on a comprehensive ceasefire, but the two countries have been in a state of hostility over the Naqqa issue, and armed conflicts have occurred from time to time.