Moscow would see any decision by the United States to give Ukraine lethal weapons as a threat to Russia's security, Russian Foreign Ministry spokesman Alexander Lukashevich said on Thursday.
Lukashevich was responding to calls in Washington and Kiev for the U.S. government to arm Ukrainian government forces fighting Russian-backed separatists in east Ukraine, though Washington says it still prefers a diplomatic solution.
He said Russia was concerned by the possibility of the United States providing Kiev with weapons, including under legislation passed last year on providing military assistance for Kiev.
"Taking into account the revanchist plans of the 'party of war' in Kiev, this is not only fraught with the escalation of the situation in the southeast (of Ukraine) but threatens the security of the Russian Federation," he told reporters.
Lukashevich accused Kiev of using weapons in east Ukraine that were having an effect similar to that of weapons of mass destruction. He also expressed concern about the creation of a joint Lithuanian-Polish-Ukrainian military force for peacekeeping operations.
Referring to NATO plans to establish command centres in eastern Europe to rapidly reinforce the region in the event of a threat from Russia, Lukashevich said creating additional forces to react near Russia's borders caused deep concern in Russia.