- Russia said its forces and their allies had taken control of Ukraine's eastern Luhansk region, after capturing the final Ukrainian holdout of Lysychansk.
- Ukraine has yet to comment after reporting heavy fighting there.
- Russia also reported explosions in its city of Belgorod, about 25 miles north of the border with Ukraine, that killed at least three people were killed and damaged and destroyed homes.
Russia said on Sunday its forces had taken control of Ukraine's eastern Luhansk region after capturing the final Ukrainian holdout of Lysychansk in heavy fighting, though Ukraine did not confirm the claim.
Control of Luhansk, a key war aim for Russia, would come after weeks of slow advances, hand Moscow a limited political win and shift the battlefield focus to neighboring Donetsk region, where Ukraine still controls substantial territory.
Driven back from the Ukrainian capital Kyiv following its Feb. 24 invasion, Russia has concentrated its military campaign on the Donbas, which includes Luhansk and Donetsk. Moscow-backed separatist proxies have been fighting there since Russia's first military intervention in Ukraine in 2014.
Russian Defence Minister Sergei Shoigu informed President Vladimir Putin that Luhansk had been "liberated," the defense ministry said after Russia earlier said its forces had captured villages around Lysychansk and encircled the city.
The minister said Russian forces and their allies in the area had "gained full control over the city of Lysychansk."
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Yuriy Sak, an advisor to Ukraine's defense minister, told Reuters over the phone that he "cannot confirm that Lysychansk is under full Russian control." Ukraine's defense ministry press service did not reply to a request for comment.
Ukrainian officials, who say references to "liberating" Ukrainian territory are Russian war propaganda, had reported intense artillery barrages on residential areas.
"Ukrainian forces likely conducted a deliberate withdrawal from Lysychansk, resulting in the Russian seizure of the city on July 2," analysts at the Institute for the Study of War, a Washington-based think tank, wrote in a briefing note.
They based their assessment on footage showing Russian forces walking casually in northern and eastern neighborhoods of Lysychansk, saying it suggested few or no Ukrainian forces remained. It said the footage included images posted on social media and geolocated to confirm where it was filmed.
West of Lysychansk, the Ukrainian city of Sloviansk was hit by powerful shelling from multiple rocket launchers on Sunday and many people were killed and wounded, the city's mayor Vadim Lyakh said.
Thousands of civilians have been killed and cities leveled since Russia invaded, with Kyiv accusing Moscow of deliberately targeting civilians. Moscow denies this.
Russia says what it calls a "special military operation" in Ukraine aims to protect Russian speakers from nationalists. Ukraine and its Western allies say this is a baseless pretext for its flagrant aggression that aims to seize territory.
While Russia would try to frame its advance in Luhansk as a significant moment in the war, it came four months into the war and at a high cost to Russia's military, said Neil Melvin of the London-based think tank RUSI.
"Ukraine's position was never that they could defend all of this. What they've been trying to do is to slow down the Russian assault and cause maximum damage, while they build up for a counteroffensive," he said.
Russia's defense ministry also said on Sunday it had struck the military infrastructure of Kharkiv, Ukraine's second-largest city in the northeast of the country, where Ukrainian forces have been digging in and building concrete fortifications after nightly shelling, a Reuters reporter said.
Ukraine says dozens of civilians have been wounded or killed in the region in recent weeks.
However, about 70 km (44 miles) from Kharkiv on the Russian side of the border, Russia also reported explosions on Sunday in Belgorod which it said killed at least three people and destroyed homes.
"The sound was so strong that I jumped up, I woke up, got very scared and started screaming," a Belgorod resident told Reuters, adding the blasts occurred around 3 a.m. (0000 GMT).
Moscow has accused Kyiv of numerous attacks on Belgorod and other areas bordering Ukraine. There was no immediate comment from Ukraine. Previously, Kyiv has not claimed responsibility but says such incidents as payback, after Russia has pounded Ukrainian urban areas into rubble.
Military base hit
In the Russian-occupied southern Ukrainian city of Melitopol, Ukrainian forces hit a military base with more than 30 strikes on Sunday, the city's exiled mayor Ivan Fedorov said in a video address on Telegram.
A Moscow-installed official said several private residential houses near the airfield were damaged, but there were no casualties.
Ukraine said its air force had flown some 15 sorties "in virtually all directions of hostilities", destroying equipment and two ammunition depots.
Also in the south, Russia said it had hit army command posts in Mykolaiv near the vital Black Sea port of Odesa, where the mayor on Saturday had reported a number of powerful explosions.
"The Russian occupiers are launching systematic rocket attacks in the direction of Mykolaiv," Ukraine's general staff said on Sunday.
Reuters could not independently verify the battlefield reports.
Ukraine has repeatedly appealed for an acceleration in weapons supplies from the West, saying its forces are heavily outgunned.
German Chancellor Olaf Scholz told broadcaster ARD on Sudan that Germany was discussing with its allies security guarantees for Ukraine after the war, though it was clear these would "not be the same as if someone were a member of NATO."