MOSCOW : Ukrainian strikes on Crimea triggered power outages in its largest city, Sevastopol, both sides reported Wednesday, as Kyiv intensifies its attempts to cut off the peninsula, which Moscow annexed in 2014.

Crimea has been forced to suspend fuel sales to the public as Ukraine's army targets Russian logistics to the region and has hit a series of oil refineries and depots across southern Russia that provide supplies.

Sevastopol's Moscow-installed governor Mikhail Razvozhayev urged residents to help vulnerable neighbours and reserve phones for emergency communication to save battery and avoid overloading the grid.

"The enemy is once again striking treacherously, attempting to deprive us of normal living conditions and sow panic," he posted.

He said some areas of the city -- where temperatures are approaching 30C -- would be without power until at least Wednesday evening.

Separate Ukrainian drone attacks killed two people in Russia's Nizhny Novgorod region, hundreds of kilometres from the front line, and one in the border region of Belgorod, the local governors reported.

And a Russian drone attack killed a 56-year-old woman in the Ukrainian border region of Kharkiv, authorities said.

Russia's defence ministry said the country's forces had destroyed more than 300 drones from Ukraine overnight, with the warring neighbours having stepped up strikes in recent weeks.

Kyiv's air force said Wednesday that Moscow launched 101 drones at Ukraine overnight, of which 95 were destroyed.

US-led talks on ending Europe's deadliest conflict since World War II have remained effectively frozen, with Washington's attention diverted towards the Middle East since launching strikes on Iran in late February.