Heavy Russian bombardment of Ukraine's battleground eastern Lugansk region and key city Severodonetsk has been "hell" for soldiers there, Kyiv said Wednesday, while insisting that defenders would hold on "as long as necessary".
Moscow's troops have been pummelling eastern Ukraine for weeks and are slowly advancing, despite fierce resistance from the outgunned Ukrainian military.
With President Vladimir Putin's forces tightening their grip on the strategically important city of Severodonetsk in the Donbas, its twin city of Lysychansk is now coming under heavier bombardment.
"The Russian army is... just destroying everything" in Lysychansk, Sergiy Gaiday, governor of the Lugansk region, which includes both cities, wrote on Telegram.
"It's just hell out there," after four months of shelling in Severodonetsk, across the Donets river, he wrote later.
"Our boys are holding their positions and will continue to hold on as long as necessary," he added.
Pro-Russian separatists claimed they were close to surrounding both Lysychansk and Severodonetsk.
"Over the past several days enormous work has been accomplished," Andrei Marochko, an officer in the separatist army of Lugansk, told Russian state television.
- 'Only grannies left' -
Taking the two cities would give Moscow control of the whole of Lugansk, allowing Russia to press further into the Donbas.
After being pushed back from Kyiv and other parts of Ukraine following their February invasion, Moscow is seeking to seize a vast eastern swathe of the country.
But daily bombardment also continues in other parts of the country.
The northeastern city of Kharkiv near the Russian border was near empty on Wednesday, AFP reporters said, a day after Russian shelling killed five people there.
Leyla Shoydhry, a young woman in a park near the opera house, said the situation was "very bad".
"Last night the building next to mine collapsed from the bombardment while I was sleeping," she said.
Roman Pohuliay, a 19-year-old in a pink sweatshirt, said most residents had fled the city.
"Only the grannies are left," he said.
In his daily address Tuesday, Ukrainian President Volodymyr Zelensky accused the Russian army of "brutal and cynical" shelling in the eastern Kharkiv region, where the governor said 15 people had been killed over the course of the day.
In a briefing Wednesday, the Russian defence ministry claimed responsibility for a missile strike it said killed a number of Ukrainian troops in the southern city of Mykolaiv.
Mayor Oleksandr Senkevych told Ukrainian television that the strike hit two firms and a school, sparking a blaze that authorities could not put out.
In the central city of Zaporizhzhia, women were training to use Kalashnikov assault rifles in urban combat as Russian forces edged nearer.
"When you can do something, it's not so scary to take a machine gun in your hands," said Ulyana Kiyashko, 29, after moving through an improvised combat zone in a basement.
Aid group Doctors Without Borders said it had gathered accounts of an "outrageous lack of care to distinguish and protect civilians" during the war in Ukraine.
Most patients it had evacuated by train blamed Russian or Russian-backed forces for a spectrum of gruesome injuries, it added.
In the southern city of Mykolaiv, two grain storage facilities were hit by Russian missile attacks, their operators Bunge and Viterra said.
- Ship leaves Mariupol -
On the Russian side, officials said Wednesday two drones had hit an oil refinery in the Rostov region bordering Ukraine, causing an explosion and a fire but no casualties.
Away from the battlefield, a senior US official in Washington said President Joe Biden and other Group of Seven leaders holding a summit this weekend in Germany will announce new measures to punish Russia for the invasion.
Moscow summoned Brussels' ambassador in a dispute with EU member Lithuania over the country's restrictions on rail traffic to the Russian outpost of Kaliningrad.
The territory is around 1,000 miles (1,600 kilometres) from Moscow, bordering Lithuania and Poland.
By blocking goods arriving from Russia, Lithuania says it is simply adhering to European Union-wide sanctions on Moscow.
The United States made clear its commitment to Lithuania as an ally in NATO, which considers an attack against one member an attack on all.
And Germany urged Russia not to "violate international law" by retaliating against Lithuania.
Also on Wednesday, a Turkish cargo ship left the Russian-occupied city of Mariupol on Ukraine's Sea of Azov coast.
Moscow and Ankara have negotiated for weeks towards getting millions of tonnes of desperately needed grain out of the war zone and on to Africa and the Middle East.
But it was not immediately clear whether the Azov Concord was carrying wheat.
Turkey's defence ministry said four-way talks would be held "in the coming weeks" between Russia, Turkey, Ukraine and the United Nations, with media reporting the meeting could happen next week.
Reporters Without Borders (RSF) said in an investigation published Wednesday that a Ukrainian photojournalist, Maks Levin, had been killed and possibly tortured by Russian troops after his capture on March 13.