Russian forces may have to advance as far as Kyiv or Lviv in Ukraine, Russia's former president Dmitry Medvedev said in an interview to Russian news agencies.
"Nothing can be ruled out here. If you need to get to Kyiv, then you need to go to Kyiv, if to Lviv, then you need to go to Lviv in order to destroy this infection," RIA Novosti quoted Medvedev as saying on Friday.
Later on Friday, Interfax reported him as saying that Russia was not planning to enter into a direct conflict with NATO and was interested in resolving the Ukraine crisis through talks.
However, he warned that any Ukrainian attempt to take the Crimean peninsula - which Moscow annexed in 2014 - would be grounds for Russia to use "absolutely any weapon" against Kyiv in response.
Medvedev warns of nuclear apocalypse
On Thursday evening, Medvedev spoke about the increased risk of nuclear war brought about by Russia's war in Ukraine, saying that "every day's delivery of foreign weapons to Ukraine brings closer the nuclear apocalypse."
He said the West now wanted to crack Russia apart into a host of weaker states and steal its vast natural resources.
"Ukraine is part of Russia," Medvedev said, adding that almost all of modern-day Ukraine had been part of the Russian empire. Russia recognized Ukraine's post-1991 sovereignty and borders in the 1994 Budapest Memorandum.
Medvedev said ties with the West would one day improve, though he said it would take a long time.
"I believe that sooner or later the situation will stabilize and communications will resume, but I sincerely hope that by that time a significant part of those people (Western leaders) will have retired and some will be dead," he said.