Russia’s defence minister has said the country’s forces have taken control of the last major Ukrainian-held city in Luhansk province, taking Moscow closer to its stated goal of seizing all of Ukraine’s Donbas region.

Sergei Shoigu told President Vladimir Putin on Sunday that Russia’s troops, together with members of a local separatist militia, “have established full control over the city of Lysychansk”, Russian news agencies reported.

Ukrainian fighters have spent weeks trying to defend Lysychansk and to keep it from falling to Russia, as neighbouring Sievierodonetsk did a week ago. A presidential adviser predicted late on Saturday that the city’s fate could be determined within days.

Ukrainian officials did not immediately provide an update on its status.

Earlier on Sunday, Luhansk’s governor said Russian forces were strengthening their positions in a gruelling fight to capture the last stronghold of resistance in the province.

Serhiy Haidai said on the Telegram messaging app: “The occupiers threw all their forces on Lysychansk. They attacked the city with incomprehensibly cruel tactics.

“They suffer significant losses, but stubbornly advance. They are gaining a foothold in the city.”

A river separates Lysychansk from Sievierodonetsk.

Oleksiy Arestovych, an adviser to Ukrainian President Volodymyr Zelensky, said during an online interview late on Saturday that Russian forces had managed for the first time to cross the river from the north, creating a “threatening” situation.

He said they had not reached the centre of the city but the course of the fighting indicated that the battle for Lysychansk would be decided by Monday.

Luhansk and neighbouring Donetsk are the two provinces that make up the Donbas, where Russia has focused its offensive since pulling back from northern Ukraine and the capital, Kyiv, in the spring.

Pro-Russia separatists have held portions of both eastern provinces since 2014, and Moscow recognises all of Luhansk and Donetsk as sovereign republics.

Syria’s government said on Wednesday that it would also recognise the “independence and sovereignty” of the two areas.

Taking Lysychansk would open the way for the Russians to move west into Donetsk province, where the sizable Ukrainian-held city of Slovyansk has come under rocket attacks several times since Russia invaded Ukraine on February 24.

Elsewhere in the war, the exiled mayor of the Russia-occupied city of Melitopol said on Sunday that Ukrainian rockets destroyed one of four Russian military bases in the city.

The Russian Defence Ministry said Ukraine also launched missile and drone attacks in western Russia, on the cities of Kursk and Belgorod, but that the aerial weapons were shot down.

Kursk regional governor Roman Starovoit said the town of Tetkino, on the Ukraine border, came under mortar fire.

The leader of neighbouring Belarus, a Russian ally, claimed on Saturday that Ukraine fired missiles at military targets on Belarusian territory several days ago but all were intercepted by an air defence system.

President Alexander Lukashenko described the alleged strike as a provocation and noted that no Belarusian soldiers were fighting in Ukraine.

There was no immediate response from the Ukrainian military.

Belarus hosts Russian military units and was used as a staging ground for Russia’s invasion of Ukraine.

Last week, just hours before Mr Lukashenko was to meet Mr Putin, Russian long-range bombers fired missiles on Ukraine from Belarusian airspace for the first time.

Mr Lukashenko has so far resisted efforts to draw his army into the war. But during their meeting, Mr Putin announced that Russia plans to supply Belarus with the Iskander-M missile system and reminded Mr Lukashenko that his government depends on economic support from Russia.