Ukrainian President Volodymyr Zelensky has condemned as terrorism a Russian drone attack on a passenger train that local officials report has killed at least four people.

Zelensky indicated that another four individuals were missing after the train, which carried over 200 passengers, was struck in Ukraine's north-eastern Kharkiv region on Tuesday.

Conversely, in Odesa, officials reported three fatalities following an overnight Russian drone assault.

The Russian government has not offered any comments regarding these attacks. In recent months, Moscow has ramped up its drone and missile strikes on Ukraine's critical infrastructure as the nation endures its harshest winter in years.

Millions of residents in Ukraine have been left without heating, electricity, and water due to these recent attacks. Since President Vladimir Putin's full-scale invasion in February 2022, Russia currently controls approximately 20% of Ukrainian territory.

In a recent social media update, Zelensky reflected that any country would classify a drone strike on a civilian train as terrorism, stressing that there is no military justification for targeting civilians. He noted that there were 18 passengers in the affected carriage.

Emergency services have released images and videos showing at least one train carriage severely damaged and still ablaze after the incident. The Kharkiv regional prosecutor's office reported that the drone strike occurred near Yazykove village, directly hitting one carriage while two additional drones exploded near the train.

The train was en route from the western border town of Chop to Barvinkove in the Kharkiv region, passing through the regional capital, Kharkiv. This route is used by both local residents and military personnel traveling home.

Meanwhile, in Odesa, local authorities stated that over 50 drones were launched by Russia overnight, targeting energy facilities and other civilian structures. Military head Serhiy Lysak reported three deaths and 25 injuries from this attack, with significant damage to a residential building.

Despite ongoing peace talks involving various parties, including the US, to find a resolution to the conflict, key territorial disputes remain unresolved, with further discussions anticipated soon.