The Russian Foreign Ministry stated on Friday that Moscow has demanded that the US and NATO legalize the agreement on non-deployment of strike systems in adjacent countries, including those that are not members of the alliance.

The ministry said in a statement, "We insist on the legal consolidation of the agreement on the non-deployment by the United States and other NATO countries of strike weapons systems that pose a threat to Russia on the territory of neighboring countries," adding that this includes "both NATO members and non-members."

Russia's foreign ministry also stated that NATO should formally withdraw a 2008 proclamation that allowed Georgia and Ukraine, two former Soviet republics, to join the alliance.

The statement added, "In the fundamental interests of European security, it is necessary to officially disavow the decision of the 2008 NATO Bucharest summit that 'Ukraine and Georgia will become NATO members." 

Su-30 escorted US reconnaissance aircraft

According to the Russian Defense Ministry's National Defense Control Center (NDCC), Russian fighter Su-30 escorted US reconnaissance aircraft P-8A over the Black Sea on Friday.

Russian radars detected a target nearing the Russian state border over the neutral seas of the Black Sea earlier in the day, according to the center.

Biden seeks united front with Ukraine amid Russian "threat"

On Thursday, US President Joe Biden called the Ukrainian president and nine NATO allies in Eastern Europe to confirm US support if Russia "attacks" Ukraine, as well as imposing "strict economic sanctions."

Biden spoke with Ukrainian President Volodymyr Zelensky, expressing the "deep" concerns of the United States and its European allies about Russia's "aggressive activities" towards Ukraine, and explaining that they "will respond with economic and other strong measures" in the event of military intervention.

President Biden reiterated the United States' commitment to Ukraine's sovereignty and territorial integrity, stressing that the United States and its allies are committed to the principle of "not taking decisions or discussions about Ukraine without its participation," according to a White House statement.