In retribution for last week's rocket attack, which resulted in the deaths of scores of Russian soldiers, the Russian military claimed to have launched lethal missile attacks against Ukrainian barracks.
Ukrainian officials denied that any casualties occurred.
Sunday, according to the Russian Defense Ministry, its missiles struck two temporary sites containing 1,300 Ukrainian troops in Kramatorsk, in the eastern Donetsk region, killing 600 of them. According to ministry spokesman Igor Konashenkov, the strikes were a reprisal for the Ukrainian onslaught in Makiivka that resulted in the deaths of at least 89 Russian service members.
Serhii Cherevatyi, a spokesman for Ukraine's military in the east, told The Associated Press that Russian strikes on Kramatorsk only harmed civilian facilities, adding, "The armed forces of Ukraine weren't affected."
According to the Donetsk regional administration, seven Russian missiles struck Kramatorsk, and two more hit Konstantynivka, although no deaths were reported. In Kramatorsk, an educational institution, an industrial facility, and garages were damaged, and in Kostyantynivka, an industrial zone was affected.
During the early morning hours of January 1, Ukrainian forces fired rockets at a facility in Makiivka, also in the eastern Donetsk region, where Russian soldiers were stationed, killing dozens of them in one of the deadliest attacks on the Kremlin's forces since the conflict began more than ten months ago.
Also on Sunday, the Ukrainian military claimed to have struck a dormitory of a medical institution in Rubizhne, a town in the Russian-occupied eastern Luhansk region, killing 14 Russian soldiers. It was stated that the number of wounded remained unknown.
Donetsk Governor Pavlo Kyrylenko reported that one person was killed and eight others were injured due to attacks on Bakhmut.
Governor Oleh Syniehubov reported that the town of Merefa in the northeastern Kharkiv area was shelled overnight, resulting in the death of one person and that two other settlements in the region were also attacked.
On Saturday, Russian soldiers ended a cease-fire that had been predominantly observed and was timed to coincide with Orthodox Christmas celebrations.