"We are receiving anti-ship capabilities and sooner or later we will target the fleet," Ukrainian Deputy Defence Minister Volodymyr Havrylov told The Times newspaper during a visit to London.

"Russia will have to leave Crimea if they wish to exist as a country," he said.

Havrylov said that the recapture of Snake Island, occupied by Russia early in the invasion, was a first step.

"We are ready to target them all over the Black Sea if we have that capability," he said.

Kremlin spokesman Dmitry Peskov reacted by saying that Havrylov's remarks confirmed the necessity of the "special military operation," as the war is officially called in Russia and which aims, among other things, to "de-Nazify" and "demilitarise" Ukraine.

"Only by such means can Ukraine be freed from such representatives of the leadership," Peskov said, according to the Russian state news agency TASS.

But Ukraine's top presidential aide on Tuesday said that Ukraine does not want the war to last into the northern hemisphere winter as this would give Russian forces time to dig in and make any Ukrainian counter-offensive more difficult.

In an interview with Ukrainian magazine NV, President Volodymyr Zelenskiy's chief of staff Andriy Yermak expressed hopes that the US arms lend-lease to Ukraine will provide a sufficient quantity of weapons before winter to allow Ukrainian troops to achieve "victory" before then.

"It is very important for us not to enter the winter. After winter, when the Russians will have more time to dig in, it will certainly be more difficult," Yermak said.

Russia was trying to "drag" Ukraine into such a protracted conflict, Yermak said.

The Kremlin has said there is no time limit to a conflict it began on February 24.

Russian President Vladimir Putin met Iranian Supreme Leader Ayatollah Ali Khamenei in Tehran on Tuesday, stressing closer ties in the face of US and European pressure over the war in Ukraine.

During his Iran visit Putin will also meet Turkish President Tayyip Erdogan to discuss a deal that would resume Ukraine's Black Sea grain exports - now blockaded by Russia - as well as peace in Syria.

It was Putin's first face-to-face meeting with a NATO leader since Russian troops invaded Ukraine.

In Moscow, former Russian president Dmitry Medvedev said that any peace in Ukraine would be the way Russia wanted it.

"Russia will achieve all its goals. There will be peace - on our terms," said Medvedev, who is now deputy head of the Kremlin's Security Council.

More than two weeks have passed since Russia's last major territorial gain - capturing the eastern Ukrainian city of Lysychansk.

Ukraine's General Army Staff said on Tuesday that Russia's forces were busy shoring up their positions in recently seized territory and mounting limited but unsuccessful ground assaults in numerous different locations.

The UK's ministry of defence, which supports Ukraine, said on Thursday it believed Russian forces were unable to advance swiftly due to personnel shortages.

Russia is facing a resources dilemma, it said, having to decide how much military hardware and personnel to commit to achieving its stated objective of seizing full control of Ukraine's eastern Donetsk region and how much to deploy to southern Ukraine to contend with a Ukrainian counter-attack.

But in a now familiar pattern, Russian missiles on Tuesday slammed into targets across Ukraine.

At least one person was killed in a missile strike on the centre of the eastern city of Kramatorsk, the regional governor said.

Buildings in a town in the Kharkiv region were also hit, with footage showing piles of rubble being cleared by excavators.

Footage from Ukraine's Odessa region showed badly damaged buildings smouldering from Russian barrages.

Oleksii Matsulevych, a spokesman for the regional administration, said on Telegram the Russian strike had injured at least four people, burned houses to the ground, and set other homes on fire.

with DPA

Australian Associated Press