The European Commission will meet Friday to give its fast-tracked opinion on Ukraine's bid for EU candidacy, a step closer to membership for the country a day after the bloc's most powerful leaders visited Kyiv as it battles Russia's invasion.

Never before has an opinion been given so quickly on EU candidacy, which must be approved by all 27 member states.

The opinion will serve as a basis for discussion at next week's EU summit, where leaders are expected to approve Ukraine's candidate status with strict conditions, though membership may take years or even decades.

The French-supplied self-propelled 155 mm Caesar howitzer has arrived on the frontlines in Ukraine, but Kyiv is urging its western allies to step up arms shipments
The French-supplied self-propelled 155 mm Caesar howitzer has arrived on the frontlines in Ukraine, but Kyiv is urging its western allies to step up arms shipments AFP / ARIS MESSINIS

France, Germany, Italy and Romania are in favour of Ukraine receiving "immediate" candidate status, French President Emmanuel Macron said in Kyiv Thursday.

Macron, German Chancellor Olaf Scholz and Italian premier Mario Draghi arrived in Ukraine by train and were joined by Romania's President Klaus Iohannis before meeting Ukrainian leader Volodymyr Zelensky, who has been lobbying allies for support.

"The most important message of our visit is that Italy wants Ukraine in the EU," Draghi said at a joint press conference.

President Emmanuel Macron offered Ukraine's President Volodymyr Zelensky France's support in his war against Russia and quest to join the EU
President Emmanuel Macron offered Ukraine's President Volodymyr Zelensky France's support in his war against Russia and quest to join the EU POOL via AFP / Ludovic MARIN

Scholz said Ukraine "belongs in the European family" and that Berlin would continue to send Kyiv weapons "for as long as it is needed".

After meeting the visiting leaders, Zelensky said he explained "essential needs in the field of defence".

"We are expecting new deliveries, above all heavy weapons, modern artillery, anti-aircraft defence systems," he said, even as Macron said France would send six Caesar self-propelled howitzers to add to the 12 already deployed on Ukraine's eastern front.

President Emmanuel Macron offered Ukraine's President Volodymyr Zelensky France's support in his war against Russia and quest to join the EU
President Emmanuel Macron offered Ukraine's President Volodymyr Zelensky France's support in his war against Russia and quest to join the EU POOL via AFP / Ludovic MARIN

Zelensky promised Ukraine was ready to put in the work to become an EU member.

Ukrainian policemen look at a building partially destroyed by shelling in Kharkiv on June 16, 2022
Ukrainian policemen look at a building partially destroyed by shelling in Kharkiv on June 16, 2022 AFP / SERGEY BOBOK

Think tank director Sebastien Maillard said he expects a positive opinion on Ukraine's EU status, but with conditions and a deadline.

"This is a very delicate exercise for the Commission because it cannot be less demanding for Ukraine than for other countries for which it has given a favourable opinion in the past. Its credibility requires the maintenance of high standards," the head of the Jacques Delors Institute said.

Russia has already "strategically lost" its war with Ukraine, suffering heavy losses and strengthening NATO, the UK's chief of defence staff said in an interview published Friday.

A Ukrainian serviceman looks at a blown-up bridge over the Lozovenka River near the village of Rus'ka Lozova near Kharkiv on June 16, 2022
A Ukrainian serviceman looks at a blown-up bridge over the Lozovenka River near the village of Rus'ka Lozova near Kharkiv on June 16, 2022 AFP / SERGEY BOBOK

"This is a dreadful mistake by Russia. Russia will never take control of Ukraine," said Tony Radakin, the country's highest-ranking military officer.

The admiral said Russian President Vladimir Putin had sacrificed a quarter of his country's army power for "tiny" gains and was running out of troops and high-tech missiles.

"Russia is failing."

Russian invasion of Ukraine
Russian invasion of Ukraine AFP / Sophie RAMIS

In eastern Ukraine, Russian forces edged closer to control of the twin cities of Severodonetsk and Lysychansk after weeks of battle.

Regional governor Sergiy Gaiday said Friday that airstrikes killed six in the area, including a mother and son, and that the number of shellings by the Russian army was growing daily.

Under near-constant bombardment by Russian forces, black-clad Sister Anastasia and a group of Orthodox nuns and pilgrims live in one of the villages closest to Ukraine's frontline.

Entrance to the religious community, in the village of Adamivka near the city of Sloviansk, is only possible with permission from the Ukrainian military.

Their complex hasn't had electricity for months, and its perimeter walls are pockmarked with shrapnel holes.

AFP journalists heard regular incoming fire from a few kilometres away, and soldiers said a cluster bomb had just fallen nearby.

Sloviansk was taken by Russia-backed separatists in 2014 but recaptured by Kyiv's forces after a months-long siege.

"This is our home, we have nowhere else to go," said Sister Anastasia.

US Agriculture Secretary Tom Vilsack called on Russia Thursday to rapidly open Ukraine's ports to permit the export of millions of tonnes of stockpiled grain.

"We shouldn't be using food as a weapon," Vilsack told reporters at the United Nations.

With global grain prices soaring and importers in the Middle East and Africa facing supply shortfalls, Moscow has demanded that economic sanctions on it be lifted in exchange for allowing the exports.

While Russia -- the largest wheat exporter in the world -- appears to be calling the shots in the grain standoff, experts say that its own agricultural sector is also bracing for tough times.

Yevgeny Shifanov, co-owner of an organic farm, says his business has felt the sting of Western sanctions and he is no longer able to sell his grain to Europe.

"We are more interested in our internal market, our economy," he told AFP.