Sergei Shoigu "inspected a command post on the front" in the direction of the southern Donetsk region, the defence ministry said, without specifying exactly where or when.

It put out a rare video of Shoigu travelling in a helicopter and talking to a soldier in front of damaged buildings.

The visit came with fighting ongoing around Bakhmut, in the longest battle of the invasion that has revealed rivalries between the conventional army and the Wagner paramilitary group.

Wagner chef Yevgeny Prigozhin said Friday his fighters had "practically encircled" Bakhmut, which has seen some of the fiercest fighting of the conflict.

Well-versed in social media, Prigozhin has for weeks been publicising the advances of his men towards the eastern city, whose symbolic importance outstrips any military significance.

Prigozhin regularly posts videos of himself alongside mercenaries, on the ground or even in a fighter jet, in contrast with Russian generals criticised for shirking the frontline.

In the latest video Friday, Prigozhin directly called on Ukrainian President Volodymyr Zelensky to abandon Bakhmut, which Russia is determined to seize as part of the wider aim of capturing the entire Donetsk region.

- 'As long as it takes' -

Zelensky has pledged to defend "fortress Bakhmut" for as long as possible, and called on allies to whip up their support to help his men do so.

On Saturday the president of the European Parliament Roberta Metsola visited Ukraine, where she called for the country to be allowed to begin its EU membership negotiations this year.

US President Joe Biden on Friday hosted German Chancellor Olaf Scholz for his first visit since the offensive, in a display of partnership after friction over supplying tanks to Ukraine.

Ahead of the meeting, the Kremlin warned weapon deliveries would only "prolong the conflict and have sad consequences for the Ukrainian people".

The United States responded to Moscow's warning against further arming Ukraine by offering another $400 million in security assistance.

When Biden and Scholz last met "Russia was amassing its troops" on the border, the US president said, adding the West had vowed to respond and "together we made good on that promise."

In reply, Scholz said it was important to send a message to Ukraine that "we will continue to (support it) as long as it takes and as long as it necessary."

The new security package featuring ammunition -- including for the HIMARS precision rocket system that Ukrainian forces have used to devastating effect against Russian troops and supply dumps.

- 'Severe pressure' -

Ukraine's defence minister Oleksiy Reznikov praised the package as "a solid investment in the future success of the Ukrainian army on the battlefield," where Western military aid has been key to Kyiv's ability to hold out and to even regain ground.

In the east however, Zelensky and several Ukrainian officials recognised an increasingly difficult situation around Bakhmut this week.

Sergiy Cherevaty, a spokesman for Ukrainian forces, said Saturday the situation was difficult but under control in the city that he described as "the epicentre" of the conflict.

The British defence ministry's intelligence update on Saturday said Ukraine was "under increasingly severe pressure, with intense fighting taking place in and around the city... Ukrainian-held resupply routes out of the town are increasingly limited".

It also said Wagner and the regular army advanced in the northern suburbs of the city, now "vulnerable to Russian attacks on three sides."

While the hotspot of the fighting is in the east of Ukraine, the death toll from a strike this week on an apartment block in southern Zaporizhzhia has now risen to 10.

Moscow says its regions bordering Ukraine are routinely shelled by Ukrainian forces, but on Thursday it reported a rare instance of fighting inside Russia.

Russian security services said a group of Ukrainian combatants had crossed into the southern Bryansk region and opened fire on a car, killing two civilians and injuring a child.

Kyiv dismissed the claims as a "deliberate provocation."