Former U.S. Ambassador to Ukraine and now a Senior Fellow at the Brookings Institution, Steven Pifer, made such a comment on his Twitter page.
"This assertion by Russian Foreign Minister Lavrov is absolutely absurd. Budapest Memorandum requires Moscow not to use or threaten any force - not just nuclear weapons - against Ukraine. Lavrov is not stupid. He knows this," the former high-ranking U.S. diplomat wrote.
Pifer responded to a statement by Lavrov, who said that Russia had not violated the Budapest Memorandum when it seized part of Ukraine and fomented an armed conflict in Donbas.
Lavrov said that Russia had not used nuclear weapons against Ukraine, as allegedly stated in the Budapest Memorandum.