KVIV -- An air-raid warning has been declared in all regions of Ukraine due to possible ballistic missile strikes, Ukrainian military authorities said.
Russia continued its regular attacks on Ukrainian cities and infrastructure overnight, launching 113 drone attacks, according to the Ukrainian Air Force on December 21. Of those drones, 57 were shot down, and 56 others were unable to reach their targets, the air force said.
The Ukrainian Air Force also said Russia had fired one surface-to-air S-400 missile at central Ukraine, but it did not cause any damage or casualties.
SEE ALSO: Ukraine Live Briefing: Russian Missile Strikes On KyivRFE/RL's Ukrainian Service reported that in the eastern Ukrainian Zaporizhzhya and Kharkiv regions downed drones damaged apartment buildings, causing casualties.
Ukraine was under a general air-raid alert for several hours on December 20 as Russia launched missile and drone attacks against the capital, Kyiv, and several other regions around the country.
Russian Advance
The latest attacks come as Ukrainian forces are struggling to stop Russia's rapid advance in the east of the country.
The Russian Defense Ministry announced on December 21 that Russian forces had taken control of the village of Kostyantynopolske in the eastern Ukrainian Donetsk region.
The claim about the village, called Ostrovsky by Russia, could not be independently confirmed by Reuters.
Meanwhile, Reuters quoted Aleksandr Khinshtein, the acting governor of Russia's Kursk region, as saying that six people, including one child, were killed in a Ukrainian missile attack on December 20 on the town of Rylsk.
Ukraine seized territory in the Kursk region in an incursion in August but has since given up about half its territorial gains.
Drones, thought to be from Ukraine, hit high-rise buildings in Kazan, the capital of Russia's republic of Tatarstan, with the attacks causing the city's airport to temporarily suspend flights. No casualties were reported.