Medvedev said the sanctions gave Russia a good reason to pull out of a dialogue on nuclear stability and, potentially, from the New Strategic Arms Reduction Treaty signed with Washington in 2010 and extended in 2021.
"We don't especially need diplomatic relations," Medvedev wrote on his verified page on Russian social network VK.Â
"It's time to padlock the embassies and continue contacts looking at each other through binoculars and gun sights."
Medvedev, a close ally of President Vladimir Putin and deputy head of Russia's security council, added that the West's "wonderful (sanctions) will not change a thing, of course".
Moscow will continue its military operations in Ukraine until it had achieved goals defined by President Putin as "demilitarisation and "denazification", he said.
"The sanctions are being imposed for one simple reason - political impotence arising from (the West's) inability to change Russia's course," Medvedev wrote.
He condemned as "really unfair" a decision by the Council of Europe, a rights watchdog, to suspend Russian membership, but added the move provided a good reason "to slam the door" for good on the organisation, giving Russia an opportunity to restore the death penalty for dangerous criminals.
Russian forces pounded Ukrainian cities including the capital Kyiv with artillery and cruise missiles on Saturday for a third day running but President Volodymyr Zelenskiy said Kyiv remained in Ukrainian hands.
