Neutral status for Ukraine (no joining NATO), a ban on using weapons to restore control over the territories occupied by Russia, and the preservation of almost 20% of Ukraine's territory for Russia, these, according to Bloomberg sources, will be Putin's possible conditions at talks with U.S. President-elect Donald Trump.

"Increasingly confident he has advantage on the battlefield in Ukraine, Russian President Vladimir Putin is determined to achieve his goal that Kyiv never joins NATO and that limits are placed on its military capacity, said the people with knowledge of Kremlin thinking," Bloomberg said on its website on Wednesday.

It is noted that the Kremlin's position is that while individual NATO members can continue to supply weapons to Ukraine under bilateral security agreements, any such weapons should not be used against Russia or to retake territory it has seized, one of the sources familiar with Moscow's preparations for possible talks said.

Russia's conditions also include maintaining at least de facto control over the nearly 20% of Ukraine under Russian control, including the Crimean Peninsula annexed in 2014, although some sources say Moscow is open to swapping some territory.