There was no immediate response to the allegations from Ukraine on Saturday.

The attack hit a hospital in the Russian-held settlement of Novoaidar and was carried out using a US-supplied HIMARS rocket launch system, the Russian defence ministry said in a statement.

“A deliberate missile strike against a known functioning civilian medical facility is without doubt a serious war crime by the Kyiv regime,” it said. “All those involved in the planning and execution of this crime will be found and held accountable.”

Civilian and military medics had been working in the hospital for many months treating local people and soldiers, it said.

Ukraine and its Western allies have accused Russian forces of frequent war crimes in the conflict in which thousands of civilians have been killed and cities and towns reduced to rubble by artillery and air raids. Russia denies targeting civilians.

‘Yet another crime’

Meanwhile, three people were killed and more than a dozen others wounded following a Russian attack on the city of Konstantynivka in eastern Ukraine, the local governor said on Saturday.

“The Russians fired at a residential neighbourhood, damaged four multi-story buildings, a hotel, garages and civilian cars,” Donetsk Governor Pavlo Kyrylenko said on social media.

Kyrylenko said rescue workers and police were at the scene, “helping people and carefully documenting yet another crime by the Russian occupiers on our land”.

Images posted on Kyrylenko’s Telegram account showed apartment buildings with blown-out windows and debris scattered around the charred remains of a car.

According to Ukraine’s defence ministry, Russia carried out attacks on Konstantynivka with multiple rocket launchers.

Almost a year into its invasion of Ukraine, Moscow is seeking to seize control of the entire Donetsk region, which it has already declared a part of Russia.

‘Deliberately destroying towns’

Ukraine said this week that Russian troops had stepped up their attacks in the east, particularly on the towns of Vugledar and Bakhmut.

Ukraine President Volodymyr Zelenskyy described the battles near Bakhmut and Vuhledar, 200km (90 miles) to the south, as “extremely acute”.

“The occupiers are not just storming our positions, they are deliberately and methodically destroying these towns and villages around them,” he said.

Ukrainian troops are locked in a “fierce combat” with Russian soldiers for control of Vuhledar as the two sides battle along the southern front. Both sides claimed success in the small administrative centre of apartment blocks surrounded by flat fields.

“The encirclement and subsequent liberation of this city solves many problems,” said Denis Pushilin, the Moscow-appointed leader of the Donetsk region.

But Kyiv said the town, which had a pre-invasion population of about 15,000, remained contested. “There is fierce combat there,” Ukrainian military spokesman Sergiy Cherevaty told local media.

‘Decisive strategic action’

Bloomberg News reported that Russia was seeking to demonstrate that its military can change the momentum of the war after months of battlefield setbacks by launching a full-out offensive.

It quoted unnamed Russian officials and advisers as saying the goal is to achieve rapid victories to gain control of the eastern regions that were annexed last year to strengthen Moscow’s hand at any future peace talks.

The US-based Institute for the Study of War (ISW) think tank agreed with the reporting.

“This report is consistent with ISW’s current assessment and forecast that the Kremlin is likely preparing to conduct a decisive strategic action – most likely in Luhansk Oblast – in the next six months intended to regain the initiative and end Ukraine’s current string of operational successes,” it said.

“ISW previously assessed that the decisive strategic action in Luhansk Oblast could be either a major offensive or a Russian defensive operation to defeat and exploit a Ukrainian counteroffensive.”

One Ukraine official said it is possible Russia will time its major offensive near the anniversary of the start of the war last year.

“It is no secret that they are preparing for a new wave by February 24,” Oleksiy Danilov, head of the Ukrainian National Security and Defense Council, told Radio Liberty on Friday.

The aim is to seize the entire Donbas – Donetsk and Luhansk – and then “to completely go beyond the borders of the regions”, said Danilov.