Ukraine says it will officially notify now-bitter rival Russia on September 21 that it will not extend its treaty of friendship, cooperation, and partnership with Moscow.
Ukrainian Foreign Minister Pavlo Klimkin said on September 19 that Kyiv will notify all relevant organizations, including the United Nations, about the move.
The 10-year treaty was originally signed on May 31, 1997, with a clause that set its automatic extension if the parties did not take action to end it. The treaty took effect on April 1, 1999.
Neither party notified the other of the wish to terminate before October 2008, thereby automatically prolonging it for another 10 years.
The treaty sets out the principle of strategic partnership, the inviolability of existing borders, respect for territorial integrity, and an obligation not to use one nation's territory to damage the other’s security.
"As friendly, equal, and sovereign states, the [parties] shall base their relations upon mutual respect and trust, strategic partnership, and cooperation," Article 1 of the treaty states.
Ukraine announced its independence from the Soviet Union on August 24, 1991, almost four months before the official dissolution of the Soviet Union.
Ties between Ukraine and Russia have worsened since Moscow illegally annexed Ukraine's Crimea region and instigated a conflict between pro-Kremlin separatists and Ukrainian armed forces in eastern Ukraine in 2014.
More than 10,300 people have been killed in the conflict.
The United States and the European Union condemned Russia’s actions in Ukraine and have slapped a series of sanctions against Moscow in reaction.