Ukrainian president Volodymyr Zelensky hailed Brussels' support for Kyiv's European Union bid as a historic achievement, as "fierce battles" raged again in Ukraine's eastern Donbas region.

The European Commission spearheaded a powerful show of solidarity on Friday by backing Ukraine for EU candidate status, an endorsement that could add it to the list of countries vying for membership as early as next week.

All 27 leaders must back Ukraine's candidacy at a Brussels summit next week but the heads of the bloc's biggest members -- France, Germany and Italy -- gave full-throated support to the idea during a highly symbolic visit to Kyiv this week.

Even though EU membership could still be years away, Zelensky called the decision a "historic achievement" and said it would "certainly bring our victory closer" against Russia.

"Ukrainian institutions maintain resilience even in conditions of war. Ukrainian democratic habits have not lost their power even now," Zelensky said in a video address.

On Friday, European Commission President Ursula von der Leyen made her support of clear by donning a striking outfit in Ukraine's national colours in blue and yellow.

"We all know that Ukrainians are ready to die for the European perspective. We want them to live with us for the European dream," she said.

'More destruction'

Zelensky's comments came as fighting raged in villages outside the eastern city of Severodonetsk in the Donbas region, which Moscow's forces have been trying to seize for weeks.

"Now the most fierce battles are near Severodonetsk. They (Russia) do not control the city entirely," the governor of the eastern Lugansk region, Sergiy Gaiday, said on Telegram.

"In nearby villages there are very difficult fights -- in Toshkivska, Zolote. They are trying to break through but failing," he said, adding that Ukrainian forces were "fighting Russians in all directions."

Gaiday said there was "more destruction" at the besieged Azot chemical plant in Severodonetsk, where he said 568 people were sheltering, including 38 children.

He also said Lysychansk -- a Ukrainian-controlled city across a river from battered Severodonetsk -- is being "heavily shelled".

Lysychansk residents were preparing to be evacuated.

"We're abandoning everything and going. No one can survive such a strike," said history teacher Alla Bor, waiting with her son-in-law Volodymyr and 14-year-old grandson.

"We are abandoning everything, we are leaving our house. We left our dog with food. It's inhumane but what can you do?"

US veterans on Russian TV

Russian state television meanwhile aired social media videos of two US military veterans who went missing last week while fighting alongside the Ukrainian army, stating they had been captured by Russian forces.

US President Joe Biden had said on Friday he did not know the whereabouts of Alexander Drueke and Andy Huynh, after their relatives lost contact with the pair.

The missing Americans -- including a third identified as a former US Marines captain -- are believed to be part of an unknown number of mostly military veterans who have joined other foreigners to volunteer alongside Ukrainian troops.

Ukrainian civilian volunteers however continue to sign up, with a group performing military exercises on Friday in fortified positions left by Russian troops in Bucha, a town synonymous with war crimes blamed on Moscow's forces.

"Most of those who are here aren't soldiers. They're just civilians who want to defend their country -- 50 percent of them have never held a weapon until today," a sergeant known as "Ticha" told AFP.

Moscow has warned Western countries against getting involved in its ex-Soviet neighbour, saying it invaded to "de-nazify and de-militarise" a country that was getting too close to the West.

Russian president Vladimir Putin said he had "nothing against" Ukraine joining the EU, saying it was "their sovereign decision to join economic unions or not" -- unlike the security risk he sees in Kyiv joining NATO.

But he said European Union membership would turn Ukraine into a "semi-colony" of the West.

Putin also insisted that the Russian invasion was not the cause of global inflation and grain shortages, blaming Western sanctions that he said threatened starvation "primarily in the poorest countries."

Eurovision battle

Moscow has turned up the pressure on Western allies by sharply reducing flows of natural gas in its pipelines to western Europe, driving up energy prices in a region dependent on Russian gas.

France's network provider said it had not received any Russian gas by pipeline from Germany since 15 June, and Italy's Eni said it expected Russian firm Gazprom to cut its supplies by half on Friday.

Ukraine was meanwhile battling on another front -- the right to host next year's Eurovision song contest after its morale-boosting win this year.

Kyiv condemned a decision by organisers to move the 2023 version of the world's biggest live music event on security grounds, possibly to Britain.

"We will demand to change this decision, because we believe that we will be able to fulfil all the commitments," Ukrainian culture minister Oleksandr Tkachenko said.