Ukraine reported a fresh wave of Russian attacks Saturday including hits on a residential block and key infrastructure facilities, as Britain became the first Western country to offer the heavy tanks Kyiv has long sought to counter the onslaught.
The British move drew a swift reaction from Moscow which warned it would only "intensify" the conflict.
Russia on Friday claimed to have captured the ravaged eastern town of Soledar following a long battle.
Victory in Soledar would be a rare achievement for Moscow after an embarrassing series of military setbacks -- although Kyiv insisted fighting was still ongoing in the town.
On Saturday morning, Ukrainian infrastructure was again under fire, officials said.
The Old New Year, a popular holiday in Ukraine, began "with a missile attack on the capital and ends with a massive shelling of the whole of Ukraine," said the country's human rights ombudsman Dmytro Lubinets.
In the major eastern city of Dnipro, an apartment building was targeted, he said. "The whole entrance was destroyed. There are people under the rubble."
Another Ukraine official said that at least five people were killed and another 27 injured in the attack on the nine-storey residential building.
- Energy infrastructure hit -
Energy facilities operator Ukrenergo said it was working on "eliminating the consequences" of fresh Russian strikes on its infrastructure.
In Kyiv, AFP journalists heard several explosions, while Ukrainian officials reported strikes on a power facility.
"There is a hit to an infrastructure facility, without critical destruction or fire," the Kyiv city administration said.
A fire broke out in a warehouse after fragments of a rocket fell, it said, adding there were no reported casualties in the capital.
In the northeastern Kharkiv region, "the enemy launched another missile attack on critical infrastructure and industrial facilities," governor Oleg Synegubov said.
Emergency blackouts were applied in "most regions" of Ukraine due to the fresh barrage of attacks, energy minister German Galushchenko said Saturday.
Attacks were also reported in the southern Zaporizhzhia region.
Russian attacks killed three people on Friday, the deputy head of presidency Kyrylo Tymoshenko said.
- UK sending first heavy tanks -
British Prime Minister Rishi Sunak on Saturday pledged to provide Challenger 2 tanks to Ukraine, making it the first Western country to supply the heavy tanks Kyiv has been calling for.
Sunak said the tanks were a sign of the UK's "ambition to intensify our support to Ukraine", according to a readout of a phone call with Ukrainian President Volodymyr Zelensky.
The Russian embassy in the UK swiftly issued a warning that "bringing tanks to the conflict zone, far from drawing the hostilities to a close, will only serve to intensify combat operations, generating more casualties, including among the civilian population".
There was uncertainty about the fate of Soledar, a salt mining outpost that Russia claimed to have captured, which Kyiv denies.
Both sides have conceded heavy losses in the battle for the town, with Moscow desperate to sell any win back home after repeated humiliations and Ukraine determined to hold -- and win back -- ground.
On an icy road near Soledar on Saturday, AFP journalists saw Ukrainian medics tending to the wounded brought from the nearby frontline.
- Fate of key city uncertain -
The Russian defence ministry on Friday announced it had "completed the liberation" of Soledar the previous day and pledged more "successful offensive operations" in the eastern Donetsk region.
In a separate statement, it praised the "courageous and selfless" forces of mercenary group Wagner for storming Soledar.
But regional governor Pavlo Kyrylenko said on national television Saturday that "Soledar is controlled by Ukrainian authorities, our military controls it."
He added that "battles continue in and outside of the city".
The industrial town with a pre-war population of about 10,000 has now been reduced to rubble through intense fighting.
Zelensky said "the difficult battle for Donetsk region continues, the battle for Bakhmut and Soledar... continues, although the enemy has concentrated its greatest forces in this direction."
Capturing Soledar could improve the position of Russian forces as they push towards what has been their main target since October -- the nearby transport crossroads of Bakhmut.
Turkey said Saturday it was ready to push for local ceasefires in Ukraine and warned that neither Moscow nor Kyiv had the military means to "win the war".
President Recep Tayyip Erdogan's foreign policy adviser Ibrahim Kalin conceded that it seemed unlikely that the warring sides were ready to strike an "overarching peace deal" in the coming months.
By Daria Andriievska