The regional governor of Lugansk – also part of the Donbas – said Western artillery would quickly help secure a Ukrainian victory for the bombarded city.
“As soon as we have long-range artillery to be able to conduct duels with Russian artillery, our special forces can clean up the city in two to three days,” governor Sergiy Gaiday said.
In his evening address to the Ukrainian people on Thursday, Zelensky said Severodonetsk and other Donbas cities “are holding on”.
Kyiv’s forces were also “gradually moving forward in the Kharkiv region” in the northeast, he added.
Up to 100 Ukrainian soldiers were being killed every day in frontline fighting and as many as 500 wounded, Defence Minister Oleksiy Reznikov said.
After being repelled from Kyiv weeks into their invasion, Russian President Vladimir Putin’s troops have refocused their offensive on the Donbas.
Pro-Russian separatists have held part of that region since 2014.
Moscow, which has repeatedly warned the West against getting involved in the conflict, said it had targeted a Ukrainian training centre for “foreign mercenaries” in the Zhytomyr region, west of Kyiv.
The Ukrainian presidency said four people were killed in a Russian air strike on Toshkivka, a village around 25km south of Severodonetsk.
Four more people were killed in fighting in Donetsk and shelling took the lives of two in Kharkiv city, it said. Another person was killed in the Mykolayiv region in the south.
In Kyiv, Ukraine’s Interior Minister Denys Monastyrsky said the capital was in no immediate danger, but troops were keeping up a line of defence around the city all the same.
Putin, meanwhile, compared his actions to Peter the Great’s conquest of the Baltic coast during his 18th-century war against Sweden.
“By fighting Sweden he was grabbing something … He was taking it back,” he told young entrepreneurs in Moscow.
“It is our responsibility also to take back and strengthen,” Putin said, in an apparent reference to Russia’s invasion of Ukraine.
‘EVERY DAY SOMETHING BURNS’
Zelensky on Thursday called for Russia to be expelled from the UN’s Food and Agriculture Organization (FAO), blaming Moscow for “causing hunger” and spurring the global grain crisis by invading his country.
Ukraine’s Black Sea ports usually export millions of tonnes of grain each year but have been blocked since the invasion, while western sanctions on Russia have prevented Moscow selling much of its grain abroad, sending food prices soaring.
The FAO warned that poor countries will suffer the most from the crisis as they were “paying more but receiving less food”.
Africa has been hard hit by the shortage, and the African Union (AU) on Thursday urged Kyiv to demine waters around Ukraine-controlled Odessa port to ease exports, warning of “serious famine” and destabilisation on the continent.
Moscow has also called for Ukraine to demine to allow out blocked grain, but Kyiv has refused for fear of a Russian attack.