Sergei Galkin has spent that time languishing in a detention center for Russian prisoners of war, the only still-captive member of an eight-person unit that crossed into Ukraine in the first days of the invasion.

The 11th attack this year on Ukraine's energy infrastructure comes amid uncertainty about how President-elect Donald Trump might deal with the conflict.

Russia's army on Thursday launched a massive attack on Ukraine's energy sector, forcing emergency power outages as temperatures dropped to freezing across the country.

Ukraine said the attacks targeted energy infrastructure. President Vladimir V. Putin said they were retaliation for Kyiv’s use of long-range American missiles.

Russia on Wednesday warned the U.S. to stop what it said was a “spiral of escalation” over Ukraine as Washington moves to quickly supply Kyiv with more weapons as the Biden administration winds down.

Energy Minister Herman Halushchenko said that Russia struck a "massive blow" at the nation's power grid, with attacks on energy infrastructure occurring throughout the country.

Vladimir Putin has threatened to target Kyiv's 'decision-making centres' with a new ballistic missile in response to Ukraine using long-range missiles on Russian territory.

Ukraine is reportedly seriously considering launching another offensive on Russian soil, following the success of its operation in the Kursk region last summer. Since August, Ukrainian forces have maintained control over a portion of the border oblast between the two warring nations.