The Budapest Memorandum, signed on 05 December 1994 by Ukraine, the U.S., Russia, and Britain, resulted in Ukraine renouncing its status as the world’s third largest nuclear power. In return, the other signatories provided “security assurances” of Ukraine’s territorial integrity, independence, sovereignty and freedom from interference. The Budapest memorandum committed Washington, Moscow and London, among other things, to “respect the independence and sovereignty and existing borders of Ukraine” and to “refrain from the threat or use of force” against that country. The United Kingdom and United States continue to support Ukraine’s sovereignty and territorial integrity.

Russo-Ukraine War - 2021 - October

Amid a stagnant diplomatic process to resolve the crisis in Donbas, the situation there worsened markedly. Thus, during September and October, both official Kyiv and representatives of pro-Russian separatist groups made mutual accusations of violating the ceasefire. The OSCE Special Monitoring Mission, which also came into focus after a brief blockade of its work in Donetsk, confirmed that the number of shellings had increased by a third compared to August in the first weeks of September. Another aggravation took place at the end of October - after the use of the Bayraktar strike drone purchased from Turkey by the Armed Forces of Ukraine to destroy the howitzer forces of the "DPR". Meanwhile, the Minsk agreements prohibit the use of drones by the parties to the conflict.

Experts and the military were actively discussing media reports about the concentration of the Russian military near the Ukrainian border. The situation is rising: information about the activity of the Russian army near the border with Ukraine on October 30 appeared in the Washington Post. The publication said that videos have recently been posted on social networks showing the movement of Russian military equipment. Further, based on the analysis of satellite images, the expert of the Washington Center for Naval Analysis (CNA) Michael Coffman wrote that the Russian 41st All-Russian Army after the completion of Russian-Belarusian exercises in September did not return to its location, but took positions near the border with Ukraine.

In October, Ukraine launched new attacks in Donbass. On 26 October 2021, the Ukrainian MoD said they struck a D-30 howitzer in the Donbas with a Turkish TB2 UCAV after two Ukrainian servicemen were wounded by artillery fire. This would be the first such use of TB2 to conduct strikes in the Donbas.

Russia, which still had about 100,000 troops stationed near Ukraine, responded with new troop movements and military exercises. The situation with the accumulation of Russian troops, which had been developing in recent weeks, was different from the escalation that took place in April this year. If in the spring it was a maneuver, now Russia, using military terminology, left a "fog of uncertainty" around its further tactical plans. There was a perception among the Ukrainian military that Russia needed a larger military contingent than the one concentrated on the border to take the invasion. This may be a misjudgment of how fast things can develop.