Moscow (CNN) Ukrainian President-elect, Volodymyr Zelensky, might be a political novice, but he's also willing to stand up to the most experienced geopolitical player on the block: Russian President Vladimir Putin.

Putin declined to send congratulations to Zelensky after his landslide election victory earlier this month. But the Kremlin leader did throw down a challenge. Last week, he signed a decree simplifying Russian citizenship for Ukrainians living in the breakaway Donetsk and Luhansk regions of Ukraine.

It was a provocative move that drew condemnation from the US. And over the weekend, Putin seemed to up the ante, saying the Russian government would consider streamlining the procedure for granting Russian citizenship to Ukrainian citizens -- not just those in separatist regions.

Russia and Ukraine have been locked in a proxy war since Moscow's annexation of the Black Sea peninsula of Crimea in 2014. Giving Russian passports to Ukrainians -- a measure Putin described last week as "purely humanitarian" -- could be seen as a pretext for further Russian meddling in Ukraine.

Zelensky, however, has countered Putin with his own offer to Ukraine's citizens.

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