Russia has shelled more than 118 Ukrainian settlements in the past 24 hours, the most since the start of the year.
Kyiv also reported a Russian attack on an oil refinery in Kremenchuk, a central industrial city.
There were no casualties reported but it took almost 100 firefighters several hours to put out the resulting blaze, Ukrainian Interior Minister Oleg Klymenko said in a post on social media.
"Over the last 24 hours, the enemy shelled 118 settlements in 10 regions. This is the highest number of cities and villages that have come under attack since the start of the year," Ukrainian Interior Minister Oleg Klymenko said on social media.
The overnight shelling killed one person in the north-east Kharkiv region, and another in the southern Kherson region, local officials said.
Moscow has fired millions of artillery shells on Ukrainian cities, towns and villages along the front lines since it launched its offensive last February, reducing several in the eastern part of the country to rubble.
Kyiv and the West fear Russia will escalate its attacks on Ukraine's energy infrastructure ahead of the winter – as Moscow did last year.
Ukraine's air force also said on Wednesday it shot down 18 of 20 Russian drones that were launched overnight, while Russia's defence ministry said it shot down two Ukrainian drones over the Bryansk and Kursk regions, which border Ukraine.
But a repeated target of previous Russian attacks, the Kremenchuk oil refinery in the central region of Poltava, was struck, setting it ablaze, according to Filip Pronin, head of the region's military administration.
"[The fire] has been extinguished. The situation is under control," he said on Telegram, adding that there were no reports yet of casualties as officials sought to gather more details of the destruction.
It was not immediately clear how the refinery was hit.
The refinery, which Mr Pronin said was not operating, has been attacked repeatedly since Russia launched its full-scale invasion of Ukraine 20 months ago.
