Ukrainian President Petro Poroshenko has signed a decree, ending Russian-Ukrainian Friendship Treaty.
The decree has been published on the official presidential website on Monday.
The decision was taken at a meeting of the country's National Defence and Security Council and is to be communicated formally to Russia and to the international community by the end of the month.
"Treaty on Friendship, Cooperation, and Partnership between Ukraine and the Russian Federation" was signed between Russian and Ukraine in 1997, describing the two countries as "strategic allies".
The treaty states that Russian and Ukraine "shall respect each other′s territorial integrity and reaffirm the inviolability of the borders existing between them".
In 2014, Russia annexed the Crimean Peninsula in violation of one of the principal articles of the treaty.
source: commonspace.eu with agencies
Azerbaijani media identified him as Bahram Hasanzada, a foreign citizen, and says he "was engaged in espionage according to instructions from foreign services, to the detriment of Azerbaijan's state security".
The report makes a number of recommendations that "aim to guide peace negotiators, policymakers, donors, and national and international civil society activists who work to promote mutual understanding and peace between the societies divided by the Nagorny Karabakh conflict".