A damaged residential building is seen at the site of the missile strike, amid Russia's invasion on Ukraine, in Mykolaiv, Ukraine June 29, 2022 in this picture obtained from social media. Courtesy of Julie Akimova - news.pn/via REUTERS
A damaged residential building is seen at the site of the missile strike, amid Russia's invasion on Ukraine, in Mykolaiv, Ukraine June 29, 2022 in this picture obtained from social media. Courtesy of Julie Akimova - news.pn/via REUTERS Reuters / JULIE AKIMOVA - NEWS.PN

Blasts shook Ukraine's southern city of Mykolaiv on Saturday as Russia's artillery helped grind out gains in the east, after a week when the civilian death toll from Russian missile strikes climbed in urban centres well behind the frontline.

"There are powerful explosions in the city! Stay in shelters!" Oleksandr Senkevych, mayor of the Mykolaiv region which borders the vital Black Sea port of Odesa, wrote on the Telegram messaging app as air raid sirens sounded.

The cause of the blasts was not immediately clear, although Russia later said it had hit army command posts in the area. Reuters could not independently verify the reports.

Kyiv says Moscow has intensified missile attacks on cities far from the main battlefields in the country's east and that it deliberately hit civilian sites. Ukrainian troops on the eastern frontlines meanwhile describe intense artillery barrages that have pummelled residential areas.

Russia says it has targeted military sites and denies aiming at civilians. Kremlin spokesperson Dmitry Peskov said "Russian Armed Forces do not work with civilian targets".

The Chief of General Staff of the Russian Armed Forces, Valery Gerasimov, inspected Russian troops involved in what Moscow calls its "special military operation", Russia's defence ministry said, although it was not clear if he was in Ukraine.

The inspection follows slow but steady gains by Russian forces with the help of relentless artillery in east Ukraine, a focus for Moscow after it narrowed its broader war goals of toppling the government following fierce Ukrainian resistance.

"Definitely they are trying to demoralise us. Maybe some people are affected by that, but for us it only brings more hatred and determination," said a Ukrainian soldier returning from Lysychansk, Ukraine's last bastion in Luhansk province.

Russia is seeking to drive Ukrainian forces out of Luhansk and Donetsk provinces in the industrialised eastern Donbas region where Moscow-backed separatists have been fighting Kyiv since Russia's first military intervention in Ukraine in 2014.

Russia's TASS news agency quoted a source close to Russia-backed forces in Luhansk saying Ukraine's last forces in Lysychansk were under intense attack. "They will be defeated in the near future if they do not surrender," the source said.

It was not possible to independently verify the report. Ukrainian officials did not immediately respond to Reuters requests for comment.

HOUSES 'BURNING DOWN'

Russian forces seized Sievierodonetsk, a major city in Luhansk this month, after some of the heaviest fighting of the four-month-old war that pounded whole districts into rubble. Other settlements now face similar bombardment.

"Private houses in attacked villages are burning down one by one," Luhansk Governor Serhiy Gaidai said on Telegram, adding that shelling stopped Lysychansk residents from dousing fires.

Ukraine has appealed for more weapons from the West, saying its forces are heavily outgunned by the Russian military.

Troops on a break from the fighting and speaking in Konstyantynivka, a market town about 115 km (72 miles) west of Lysychansk, said they had managed to keep the supply road to the embattled city open, for now, despite Russian bombardment.

"We still use the road because we have to, but it's within artillery range of the Russians," said one soldier, who usually lives in Kyiv but asked not to be named, as comrades relaxed nearby, munching on sandwiches or eating ice cream.

"The Russian tactic right now is to just shell any building we could locate ourselves at. When they've destroyed it, they move on to the next one," the soldier said.

Russia has also struck cities well behind the frontline. A missile slammed into an apartment block near the southern port city of Odesa on Friday, which the authorities said killed at least 21 people. A shopping mall was hit on Monday in the central city of Kremenchuk, leaving at least 19 dead.

Ukrainian President Volodymyr Zelenskiy denounced the strikes in an address on Friday as "conscious, deliberately targeted Russian terror and not some sort of error or a coincidental missile strike". Moscow has denied such charges.

Thousands of civilians have been killed and cities levelled since Russia invaded Ukraine on Feb. 24 in what Moscow calls a "special military operation" to root out nationalists. Ukraine and its Western allies say it is an unprovoked war of aggression.

Despite being battered in the east, Ukrainian forces have made some advances elsewhere, including forcing Russia to withdraw from Snake Island, a Black Sea outcrop about 140 km (85 miles) southeast of Odesa that Moscow captured at the start of the war.

Russia had used Snake Island to impose a blockade on Ukraine, one of the world's biggest grain exporters and a major producer of seed for vegetable oils. The disruptions have helped fuel a surge in global grain and food prices.

Russia, also a big grain producer, denies it has caused the food crisis, blaming Western sanctions for hurting its exports.