Russia has reacted sharply to media reports that the US administration is finalizing plans to send the Patriot missile defense system to Ukraine.

CNN and other media outlets have quoted US officials as saying the military aid could be announced as early as this week.

The Russian Embassy in Washington issued a statement on Wednesday calling the proposed transfer "yet another provocative step." It said the move could "lead to unpredictable consequences."

Russian forces have repeated missile and drone attacks on Ukraine's energy infrastructure, which could lead to serious power shortages in freezing weather.

Meanwhile, Russian presidential spokesperson Dmitry Peskov suggested on Wednesday that President Vladimir Putin's annual address to the federal assembly may not happen until next year.

A US think tank, the Institute for the Study of War, says Putin initially planned to declare a victory in Ukraine in his annual address.

It points out that Russian forces, however, have not achieved notable results in their operations since July.

The US think tank says, "Putin may not be confident in his ability to justify the cost of his war upon Russian domestic and global affairs when addressing the Russian public and elites."