Russia said Sunday that trains carrying more bodies of Ukrainian soldiers were due to depart towards the Ukrainian border, escalating a spat with Kyiv over a prisoner of war swap.

Both Russian and Ukrainian forces have continued to carry out strikes amid the stalled exchange efforts. The Russian Defense Ministry said on Saturday that the military conducted group strikes using long-range precision weapons and drones against targets in Ukraine, following six similar attacks over the past week.

Russian presidential aide urges Ukraine to "strictly adhere to the schedule and all agreements reached, and to immediately begin exchange"