Kyiv (Ukraine) (AFP) - Ukraine on Monday said its forces clawed back clutches of territory from Russia last week as part of its counteroffensive, as Russia’s security service said it foiled an assassination attempt on the head of Moscow-annexed Crimea.

Ukrainian forces, which have faced intense resistance and made gradual progress in their counteroffensive launched last month, have urged Western allies for more military support.

“Over the past week… the area liberated (in the east) was increased by nine square kilometres (four square miles),” Deputy Defence Minister Ganna Malyar said.

Ukrainian forces also wrested another 28 square kilometres in the south, she said, with “successes” along the front near Melitopol and Berdyansk.

Ukraine’s forces have gained over 158 square kilometres in the south since the start of the counteroffensive, Malyar said.

Kyiv’s troops are coming up against heavily entrenched Russian defensive positions both along the southern and eastern fronts.

Russian forces are also on the offensive, and in recent days launched new assaults towards Svatove, in the eastern Lugansk region.

On Sunday, Malyar said Russia was advancing near Svatove, as well as near Avdiivka, Mariinka and Lyman.

“The situation is quite complicated,” she said.

- ‘Fierce’ fighting -

Malyar said Ukrainian troops were fighting “fierce” battles around the eastern flashpoint city of Bakhmut.

Bakhmut was seized by Russian forces spearheaded by the Wagner mercenary group.

Last month the head of the Wagner mercenary group, Yevgeny Prigozhin, led his forces in a rebellion against Moscow’s top military brass, which Russian President Vladimir Putin said posed a threat to the country’s very survival.

Following the rebellion, the Kremlin gave fighters from the private army the choice of signing contracts with the Russian defence ministry, returning to civilian life or going into exile in Belarus, whose authoritarian leader is an ally of Putin.

Russia however said there was no need for further mobilisation to replace the Wagner troops that left the battlefield, even as Kyiv is leading its counteroffensive.

Kyiv aims to gain back its territories in the east and south, including the Crimea peninsula, annexed by Russia in 2014.

In Crimea, the Russian security service (FSB) said Monday it had foiled an assassination attempt on the Moscow-installed head of Crimea, Sergei Aksyonov.

The FSB said it had detained a suspect – “a Russian national born in 1988 who had been recruited by officers of Ukraine’s Security Service (SBU)”.

It added that the suspect was held while “removing the explosive device from its hiding place”.

- ‘Pisses me off’ -

Aksyonov thanked the FSB for preventing the attack and said the perpetrators would be punished.

“Only by fulfilling the objectives of the military operation in Ukraine… can we completely get rid of the terrorist threat from the side of Kyiv,” he said.

Moscow annexed Crimea from Ukraine after a referendum widely regarded as a sham by Kyiv and Western countries.

Increased attacks on Russian-occupied territories preceded the highly-expected counteroffensive, which Ukraine launched last month after accumulating Western-made weapons.

Ukrainian officials have expressed frustration at the slow deliveries of weapons promised by the West.

Ukraine’s military commander-in-chief Valery Zaluzhny told the Washington Post it “pisses me off” that some in the West complain about the slow start and progress to the long-awaited push against Russian occupying forces.

He also complained he has a fraction of the artillery shells that Russia is firing.

“A lot of people die every day – a lot. Just because no decision has been made yet,” Zaluzhny said.

Late Sunday freedom of expression group PEN said a Ukranian writer wounded in a Russian missile strike on a restaurant last week had died.

Victoria Amelina, 37, was injured when a Russian missile destroyed the Ria Pizza restaurant in the eastern city of Kramatorsk on Tuesday, killing 12 people, including children, and wounding dozens.