Kyiv has been rocked by several explosions a day after officials said troops had recaptured a swathe of the battlefield city of Sievierodonetsk in a counter-offensive against Russia.
"Several explosions in Darnytskyi and Dniprovskyi districts of the capital," Kyiv Mayor Vitali Klitschko wrote on the Telegram messaging app.
"Services are already working on site. More detailed information — later."
A Reuters witness saw smoke in the city after the explosions.
At least one person was hospitalised but no deaths had been reported as of early on Sunday, Mr Klitschko said.
Other officials said the Russian bombardment appeared to be targeting the railway network.
Despite continuing Russian attacks on Ukraine and the widespread destruction, Kyiv has been relatively calm in recent weeks after Moscow turned its military focus to the east and south, especially an intense battle for Sievierodonetsk.
Russia has concentrated its forces on the factory city for one of the biggest ground battles of the war, with Moscow appearing to bet its campaign on capturing one of the two eastern provinces it claims on behalf of separatist proxies.
Serhiy Gaidai, the governor of the Luhansk region that includes Sievierodonetsk, said on Sunday that Ukrainian forces controlled about half the city after recapturing a large chunk from Russian troops.
"It had been a difficult situation, the Russians controlled 70 per cent of the city, but over the past two days they have been pushed back," Mr Gaidai said on Ukraine's television.
The claims could not be independently verified.
Britain's defence ministry said on Sunday that Ukrainian counterattacks there over the past 24 hours were likely to blunt any operational momentum that Russian forces had previously gained.
Moscow said its own forces were making gains in the city.
Ukraine's army said Russian forces continued to mount assault operations with the aid of artillery and controlled the eastern part of Sievierodonetsk.
"The situation is tense, complicated," Mayor Oleksandr Stryuk told national television on Saturday, saying there was a shortage of food, fuel and medicine.
"Our military is doing everything it can to drive the enemy out of the city."
Both sides claim to have inflicted huge casualties in the fighting, a battle that military experts say could determine which side has the momentum for a prolonged war of attrition in coming months.
Ukrainian officials said at least eight people were killed and 11 injured in Russian shelling in the neighbouring Donetsk region.
Donetsk and Luhansk make up the wider Donbas region where Russia hopes to take control.
'It is Russia that humiliates itself', Kuleba says
In the diplomatic sphere, Kyiv rebuked French President Emmanuel Macron for saying it was important not to "humiliate" Moscow.
"We must not humiliate Russia so that the day when the fighting stops we can build an exit ramp through diplomatic means," Mr Macron said in an interview published on Saturday, adding he was "convinced that it is France's role to be a mediating power".
Ukrainian Foreign Minister Dmytro Kuleba tweeted in response: "Calls to avoid humiliation of Russia can only humiliate France and every other country that would call for it".
"Because it is Russia that humiliates itself. We all better focus on how to put Russia in its place. This will bring peace and save lives."
Ukrainian President Volodymyr Zelenskyy offered a stark message: "The terrible consequences of this war can be stopped at any moment… if one person in Moscow simply gives the order," he said, in an apparent reference to Russian President Vladimir Putin.
"The fact that there is still no such order is obviously a humiliation for the whole world."
Mr Putin will discuss the war in an interview due to be broadcast on national television on Sunday.
In a brief excerpt aired on Saturday, he said Russian anti-aircraft forces have shot down dozens of Ukrainian weapons and are "cracking them like nuts".
Ukraine says it aims to push Russian forces back as far as possible on the battlefield, counting on advanced missile systems pledged in recent days by the United States and Britain to swing the war in its favour.
Asked about Macron's mediation offer on national television, Mr Zelenskyy's adviser Mykhailo Podolyak said there was "no point in holding negotiations" until Ukraine received all the pledged weapons, strengthened its position and pushed Russian forces "back as far as possible to the borders of Ukraine".
Moscow has said the Western weapons will pour "fuel on the fire" but will not change the course of what it calls a "special military operation" to disarm Ukraine and rid it of nationalists.
In the war, which marked its 100th day on Friday, tens of thousands are believed to have died, millions have been uprooted from their homes and the global economy has been disrupted.
Ukraine is one of the world's leading sources of grain and cooking oil, but those supplies were largely cut off by Russia's closure of its Black Sea ports, with more than 20 million tonnes of grain stuck in silos.
The situation is contributing to a global food crisis, with many countries in the Middle East and Africa on the verge of famine.
Putin warns Russia will strike new targets if missiles supplied
President Vladimir Putin warned the West that Russia would strike new targets if the United States started supplying Ukraine with longer-range missiles, the TASS news agency reported on Sunday.
If such missiles are supplied, "we will strike at those targets which we have not yet been hitting", Mr Putin was quoted as saying in an excerpt of an interview with Rossiya-1 state television channel.
Mr Putin did not name the targets Russia planned to pursue if Western countries began supplying Ukraine with longer-range missiles.
He said the "fuss" around Western weapon supplies to Ukraine was designed to drag out the conflict.
US President Joe Biden announced plans last week to give Ukraine precision HIMARS rocket systems after receiving assurances from Kyiv that it would not use them to hit targets inside Russia.
Ukrainian officials believe the supply of such rockets could be a game-changer in countering the Russian offensive.
ABC/wires
