The Russian Defence Ministry said on Friday that its strategic bombers had carried out what it called high-precision missile strikes on Ukrainian army reserve units overnight to prevent them from getting to the frontline.
The attacks, the first large-scale Russian air strikes in nearly two months, were reported to have killed at least 17 people, according to Ukrainian authorities. They said the victims included several children who were killed in strikes on homes.
Russia's defence ministry, which denies deliberately targeting civilians, said the aim of the strikes was to prevent Ukraine - which says it is poised to launch a counter-offensive against Russian forces - from bringing reserve forces to the front line.
"Overnight, the Russian Air Force carried out a collective rocket strike using long-range high-precision weapons targeting temporary deployment sites of Ukrainian army reserve units," Russian Defence Ministry spokesman Igor Konashenkov told a briefing.
"The target of the strike was achieved. All designated facilities were struck. The advance of the enemy's reserves into combat zones was thwarted," Konashenkov said. The Ukrainian military said it had shot down 21 out of 23 cruise missiles fired by Russia.
(Reporting by Reuters; Editing by Andrew Osborn/Mark Trevelyan)