Russia fires barrage at multiple cities in Ukraine.

Editor's note: This is a continuing story and will be updated as information becomes available. Russia overnight on Dec.

29 unleashed a barrage of missiles and UAVs targeting multiple cities across Ukraine, local media reported. Six explosions from S-300 missiles were recorded in Kharkiv as Russia continues to pound the area with airstrikes.

In Lviv in western Ukraine, explosions from drone strikes were recorded as air defenses operated in the city. Strategic bomber aircraft capable of firing long-range missiles were reportedly detected in Russian airspace near Ukraine's Sumy Oblast. In Kyiv, officials warned residents to take shelter as Russian Shahed UAVs were detected in the area.

Residents of Poltava, Myrhorod, and Cherkasy - cities in central Ukraine - were advised to take shelter.

Moscow has stepped up airstrikes in key cities in Ukraine as winter sets in.

President Volodymyr Zelensky admitted during a visit to Washington earlier this fall that the season ahead "will be tough" as his nation holds off Russian forces while U.S. support from Congress faces continuing uncertainty.