Ukraine is fighting to defend the ruined city of Bakhmut because the battle is pinning down Russia's best units, an aide to President Volodymyr Zelenskyy has said.
Mykhailo Podolyak said the fight for the beleaguered town was degrading Moscow’s elite troops before a planned Ukrainian spring counter-offensive.
The comments, by Mr Podolyak, were the latest signal of a shift by Kyiv this week to continue the defence of the small eastern city, site of some of the war's bloodiest battles, as Moscow tries to secure its first victory in more than half a year.
"Russia has changed tactics," he said in an interview published by Italy's La Stampa newspaper.
"It has converged on Bakhmut with a large part of its trained military personnel, the remnants of its professional army, as well as the private companies."
"We, therefore, have two objectives: to reduce their capable personnel as much as possible, and to fix them in a few key wearisome battles, to disrupt their offensive and concentrate our resources elsewhere, for the spring counter-offensive. So, today Bakhmut is completely effective, even exceeding its key tasks."
Russia has made Bakhmut the main target of a winter offensive involving hundreds of thousands of reservists and mercenaries. It has succeeded in capturing the eastern part of the city and the outskirts to the north and south, but has so far failed to close a ring around Ukrainian defenders there.
Kyiv, which had seemed at the start of March to be planning to withdraw to positions west of the city, announced at the start of this week that its generals had decided to reinforce troops in Bakhmut and fight on.
In a morning update, the Ukrainian general staff reported a large number of attacks along the front and said "the enemy is not halting its attacks on Bakhmut".
The intense trench warfare, described by both sides as a meat grinder, has led to huge losses. But Kyiv's decision to stay and fight rather than withdraw was a sign it believes Russia's losses are far worse than its own.
Moscow says capturing Bakhmut would be a step towards capturing all of Ukraine's Donbas industrial region, a major objective. Russian Defence Minister Sergei Shoigu said on Tuesday seizing the city would punch a hole in Ukrainian defences and let Moscow advance deeper.
After making gains throughout the second half of 2022, Ukrainian forces have been mostly on the defensive since mid-November, while Russia has gone on the attack with troops called up in its first mobilisation since the Second World War.
But apart from around Bakhmut, the Russian winter offensive has largely failed. Meanwhile, Kyiv is awaiting a surge in Western military aid expected in coming months for an offensive once muddy ground dries in late spring.
Kyiv and the West also saw signs of exhaustion in Russia's latest mass salvo of missile strikes on Ukrainian targets.
Russia fired hundreds of millions of dollars worth of missiles across Ukraine on Thursday, including an unprecedented six of its hypersonic kinzhal missiles, touted as a superweapon for which Nato has no answer. It is only believed to possess a few dozen kinzhals.
The barrage killed civilians, including a family buried under rubble while they slept in their homes near Lviv, 700 km from the battlefield. But otherwise it appeared to have achieved little, with damaged power systems mostly quickly restored.
The worst damage appears to have been in the eastern city of Kharkiv, where the regional governor said about 500,000 people were still without power on Friday morning.
It had been three weeks since the last similar Russian attack, the longest lull since such strikes began in October. Previously, Moscow had been unleashing such attacks roughly every week, challenging Ukraine's ability to repair infrastructure before the next onslaught.
Meanwhile, Ukraine handed suspicion notices on Friday to three former top managers of aircraft manufacturer Antonov for obstructing the country's military and allowing Russia to destroy the iconic giant "Mriya" cargo plane at the start of the full-scale war.
The Prosecutor General's Office and the SBU security service said the former officials prevented the Ukrainian National Guard from building fortifications at a key airport on the outskirts of the capital Kyiv in January to February last year as the threat of Russia's full-scale invasion loomed.
The SBU and prosecutors said in statements that two of the suspects were detained and the former general director of Antonov was declared a wanted person. The suspects, who were not named, could face up to 15 years in prison.