Smoke rises after an airstrike in Lviv, Ukraine. File/Reuters
Ukrainian President Volodymyr Zelensky said his country's forces were "doing everything" to stop the Russian offensive, with fierce battles in the east and the south.
Kyiv said on Friday it had launched new air strikes in the captured southern region of Kherson, one of the first areas to be taken by Russia after the February 24 invasion.
But Zelensky said Friday "very difficult battles" were ongoing, including in the eastern Donbas region where Moscow has concentrated its firepower, especially around the eastern industrial city of Severodonetsk.
Ukrainian President Volodymyr Zelensky speaks in Kyiv. File photo
"Ukrainian troops are doing everything to stop the offensive of the occupiers," Zelensky said in an address.
"As much as the heavy weapons, modern artillery — all that we have asked and continue to ask our partners for — allow them to."
In the Mykolaiv region near the front line in the south, the regional governor stressed the urgent need for international military assistance.
"Russia's army is more powerful, they have a lot of artillery and ammo. For now, this is a war of artillery... and we are out of ammo," Vitaliy Kim said.
Ukrainian forces are "doing everything" to stop the Russian offensive.
"The help of Europe and America is very, very important because we just need ammo to defend our country."
Zelensky said in his address that Ukraine must "not allow the world to divert its attention away from what is happening on the battlefield".
In the town of Lysychansk, located just across a river from Severodonetsk, people told AFP about their stark choice: stay and brave the shelling, or flee and abandon their homes.
Yevhen Zhyryada, 39, said the only way to access water was by heading to a water distribution site in the town.
"We have to go there under shelling, and under fire," he said.
"This is how we survive."
An official with the Russia-backed Donetsk People's Republic said Pisky, on the frontlines just 10 km (6 miles) northwest of provincial capital Donetsk, was under control of Russian and separatist forces.
Both sides have expended large amounts of weaponry in what has become a grinding war of attrition for the eastern region of coal mines and factories known as the Donbas, placing huge strains on their resources and stockpiles.
The city has become the main target of the Russian offensive in the Donbas as the Kremlin's invasion grinds on in a war of attrition that has seen cities laid waste by artillery barrages.
Governor Dmytro Zhyvytskyy posted photographs of the charred shell of a four-story building and rescuers searching rubble. In a later Facebook post, he said many Russian soldiers and some local residents also were killed during the fighting on Sunday.
“Without them, we would not have written the letters of our lives.. Without them, our countries would not have advanced in science,”Sheikh Mohammed tweeted on Wednesday.
This was announced by Mohammed Hassan Khalaf, through the "Direct Line" programme, via Sharjah Radio, showing an image of the location of Salem Bin Abdullah Al Owais Mosque.
A trial opened on Wednesday in Spain over a 2013 train derailment that killed 80 passengers and injured 145 others. Prosecutors are seeking four-year prison sentences for the train driver and for a former security director at state-owned rail infrastructure company ADIF.