Russian shelling has killed at least eight civilians in Ukraine over the past 24 hours and wounded 25 more, Ukrainian officials said.

Meanwhile, Pro-Russia separatists said attacks by Ukrainian forces have killed four civilians.

The Ukrainian presidential office said Russian forces targeted cities and villages in the country’s south-east, with most civilian casualties occurring in Donetsk province, where Russia has stepped up its offensive in recent days.

Governor Pavlo Kyrylenko said in a Telegram post that two people died in the city of Avdiivka, which is located in the centre of the province, and the Donetsk cities of Sloviansk, Krasnohorivka and Kurakhove each reported one civilian killed.

“Every crime will be punished,” he wrote.

Mr Kyrylenko urged the province’s more than 350,000 remaining residents to flee late on Tuesday, saying that evacuating Donetsk is necessary to save lives and allow the Ukrainian army to put up a better defence against the Russian advance.

Donetsk is part of the Donbas, a mostly Russian-speaking industrial area where Ukraine’s most experienced soldiers are concentrated.

Russian President Vladimir Putin on Monday declared the complete seizure of the region’s other province, Luhansk, after Ukrainian troops withdrew from the last city under their control.

Luhansk governor Serhiy Haidai on Wednesday denied that the Russians had completely captured the province.

Heavy fighting continued in villages around Lysychansk, the city Ukrainians soldiers withdrew from and which Russian troops took on Sunday, he said.

“The Russians have paid a high price, but the Luhansk region is not fully captured by the Russian army,” Mr Haidai said.

“Some settlements have been overrun by each side several times already.”

He accused Russian forces of scorched-earth tactics, “burning down and destroying everything on their way”.

Up to 15,000 residents remain in Lysychansk and some 8,000 in the nearby city of Sievierodonetsk, which Russian and separatist fighters seized last month, Mr Haidai said.

Pro-Russian separatists have fought Ukrainian forces and controlled much of the Donbas for eight years.

Before Russia invaded Ukraine on February 24, Mr Putin recognised the independence of the two self-proclaimed separatist republics in the region.

Separatist authorities in Donetsk said on Wednesday that four civilians had been killed and another 14 wounded in Ukrainian shelling over the past 24 hours.

News reports said shelling hit an ammunition depot on Tuesday, triggering massive explosions.

Since Russian forces failed to make inroads in capturing Kyiv, Ukraine’s capital, Moscow has concentrated its offensive on seizing the remaining Ukrainian-held areas of the Donbas.

To the north of Donetsk, Russian forces also hit Kharkiv, Ukraine’s second-largest city, with missile strikes overnight, the Kharkiv regional governor said Wednesday on Telegram.

Three districts of the city were targeted, governor Oleh Syniehubov said.

Three people, including a toddler, sustained injuries, according to the governor.

A missile struck a building where military registration takes place.

A government building next door remained intact, and people just steps away glanced at the wreckage in passing.

Closer to the front line and in a more abandoned district of the city, first responders crunched through the debris of another overnight attack at the national teaching university in Kharkiv.

Pages of dusty textbooks flapped in the breeze.

The attacks indicated the city, which is located close to the Russian border, is unlikely to get a reprieve as the war grinds on into its fifth month.

Russia’s Defence Ministry said its air force killed up to 100 Ukrainian troops and destroyed four armoured vehicles in Kharkiv.

The ministry’s chief spokesman, Igor Konashenkov, said air-launched high precision missiles also destroyed two Himars multiple-launch rocket systems the US sent to Ukraine.

He said ammunition warehouses were also destroyed in Donetsk province, while a Ukrainian air-defence radar and a camp housing foreign fighters were hit in the southern Ukraine’s Mykolaiv region.

The Ukrainian military denied Moscow’s claims, calling them “nothing more than a fake” in a Facebook post.

In other developments:

— European Commission president Ursula von der Leyen said the 27-nation European Union needs to make emergency plans to prepare for a complete cut-off of Russian gas in the wake of the Kremlin’s war in Ukraine. The EU has already imposed sanctions on Russia, including on some energy supplies, and is trying to find other sources. But Ms von der Leyen said the bloc needed to be ready for shock disruptions coming from Moscow.

— European Union politicians voted to support a plan by the bloc’s executive commission to include natural gas and nuclear power in its list of sustainable activities. Environmentalists accused the EU of “greenwashing”. One argument for rejecting the proposal was that it could boost gas sales that benefit Russia. The European Commission said it had a letter from the Ukrainian government backing its stance.

— A court in Russia ordered a pipeline bringing oil from Kazakhstan to Europe to be halted for 30 days for what it said were environmental violations, Russian media reported. The ruling by a court in Russia’s southern city of Novorossiysk cited the results of a recent inspection of the Caspian Pipeline Consortium. Kazakh leader Kassym-Jomart Tokayev told EU Council president Charles Michel on Tuesday that Kazakhstan “is ready to use its hydrocarbon potential in order to stabilise the situation on the world and European markets”.