Ukrainian President Volodymyr Zelenskyy denied Sunday that Russian forces have fully seized the last Ukrainian stronghold in Luhansk province.
The city of "Lysychansk is still being fought for," he told a news conference with Australia's visiting prime minister.
Russia claimed control of the city earlier Sunday.
A Ukrainian official, however, denied Moscow's control was complete. If confirmed, Russia's claim that it seized the last stronghold of resistance in Luhansk province would bring its forces one step closer to achieving one of President Vladimir Putin's major goals, capturing the entire Donbas, where a pivotal battle of the war is unfolding.
Defense Minister Sergei Shoigu told Putin that Russia's troops, together with members of a local separatist militia, "have established full control over the city of Lysychansk," according to a ministry statement published Sunday.
As is typical with such descriptions, the Russian statement said the seizure of the city marked "the liberation of the Luhansk People's Republic," one of two Ukrainian provinces that have declared their independence and are recognized by Moscow.
The BBC quoted a Ukrainian military spokesman as denying Lysychansk was under full Russian control. Yuriy Sak told the BBC that it will "not be game over" for the Donbas region even if Russia captures all of Luhansk.
"For Ukrainians, the value of human life is a top priority, so sometimes we may retreat from certain areas so that we can retake them in the future," Sak added.
Oleksiy Arestovych, an adviser to the Ukrainian president, had predicted late Saturday that Lysychansk's fate could be determined within days. Earlier Sunday, Luhansk's governor said Russian forces had strengthened their positions.
"The occupiers threw all their forces on Lysychansk. They attacked the city with incomprehensibly cruel tactics," Gov. Serhiy Haidai said on the Telegram messaging app. "They suffer significant losses, but stubbornly advance. They are gaining a foothold in the city."
Ukrainian fighters spent weeks trying to keep Lysychansk from falling to Russia, as neighboring Sievierodonetsk did a week ago in bloody battles that devastated both cities. The capture of Lysychansk would give the Russians a stronger base to intensify attacks on the second province in the Donbas, Donetsk.
Since pulling back from northern Ukraine and the capital, Kyiv, after setbacks early in the war, Russia has focused its offensive on the Donbas, a region of mines and factories where Moscow-backed separatists have been fighting Ukrainian forces since 2014.
If Russia prevails there, Ukraine would lose not only land but perhaps the bulk of its most capable military forces, opening the way for Moscow to grab more territory and strengthen its ability to dictate terms to Kyiv.
Already, Russian forces have concentrated rocket attacks on the sizable Ukrainian-held city of Slovyansk in Donetsk. New attacks were reported in the city Sunday. At least six people were killed, regional government spokeswoman Tatyana Ignatchenko told Ukrainian TV.
Kramatorsk, another major city in the Donetsk region, also came under fire, the regional administration said.
Far from the fighting in the east, Australian Prime Minister Anthony Albanese on Sunday visited a town near the capital that was severely damaged early in the war. Albanese called the destruction in Irpin "devastating."
"These are homes and these are livelihoods and indeed lives that have been lost here in this town," he said.
Elsewhere, the exiled mayor of the Russia-occupied city of Melitopol said Sunday that Ukrainian rockets destroyed one of four Russian military bases in the city.
Attacks were also reported inside Russia, in a revival of sporadic apparent Ukrainian strikes across the border. The governor of the Belgorod region in Western Russia said fragments of an intercepted Ukrainian missile killed four people Sunday. In the Russian city of Kursk, two Ukrainian drones were shot down, according to the Russian Defense Ministry.
Kursk regional governor Roman Starovoit said the town of Tetkino, on the Ukraine border, came under mortar fire.
