Russia claimed Friday that its forces had taken control of the salt-mining town of Soledar in eastern Ukraine overnight after days of relentless fighting, claiming Moscow's first big battlefield gain after half a year of military setbacks.

Reuters could not immediately verify the situation in the town. Earlier on Friday, Kyiv said fighting was still continuing there, after what it described as a "hot" night.

Russia said the capture of Soledar would make it possible to cut off Ukrainian supply routes to the larger nearby city of Bakhmut and trap remaining Ukrainian forces there. Russia has been trying to seize Bakhmut for months in brutal warfare.

"The capture of Soledar was made possible by the constant bombardment of the enemy by assault and army aviation, missile forces and artillery of a grouping of Russian forces," Moscow's Defence Ministry said.

Kyiv says Russia threw wave upon wave of soldiers and mercenaries into a pointless fight for a bombed-out wasteland at Soledar and U.S. officials said a Russian victory there, or even in Bakhmut, would make little difference to the overall war.

Soledar, with a pre-war population of just 10,000, sits above cavernous salt mines. Bakhmut, 10 times larger, is a substantial provincial district hub.

"Even if both Bakhmut and Soledar fall to the Russians, it's not going to have a strategic impact on the war itself," U.S. National Security Council spokesman John Kirby told reporters at the White House on Thursday, "and it certainly isn't going to stop the Ukrainians or slow them down."

The Wagner ultra-nationalist mercenary company run by an ally of President Vladimir Putin had claimed to have captured Soledar on Wednesday, but until now Russia's defense ministry had stayed silent.

"The night in Soledar was hot, battles continued," Ukraine's Deputy Defence Minister Hanna Malyar wrote on the Telegram messaging app.

"The enemy threw almost all the main forces in the direction of Donetsk and maintains a high intensity of offensive. Our fighters are bravely trying to maintain the defense," she said, referring to the Donetsk region which includes Soledar.

"This is a difficult phase of the war, but we will win. There is no doubt."

Outside Soledar on Thursday, Ukrainian soldiers were dug into well-fortified trenches in the wintry woods. Explosions echoed in the distance.

A 24-year-old soldier using the call-sign BUK, told Reuters the intensity of shelling had risen by around 70 percent, but forces were still holding their positions.

"The situation is difficult but stable. We're holding back the enemy ... we're fighting back."

Ukrainian officials said on Thursday more than 500 civilians were trapped inside Soledar, including 15 children.

In an overnight video address, Ukrainian President Volodymyr Zelenskiy thanked two units in Soledar he said were "holding their positions and inflicting significant losses on the enemy." He did not give more details.

Meat grinder

The front lines in Ukraine have barely budged for two months since Russia's last big retreat in the south. Meanwhile, the battles around Bakhmut and Soledar became what both sides called a "meat grinder" – a brutal war of attrition claiming the lives of thousands of soldiers needed for decisive battles ahead.

The new year has brought important pledges of extra Western weapons for Ukraine, which is seeking armor to mount mechanized battles against Russian tanks. Last week, France, Germany and the United States pledged to send armored fighting vehicles.

In recent days, the focus has been on main battle tanks, which Western countries have yet to provide. On Friday, Finland joined Poland in promising to send German-made Leopard tanks to Ukraine as part of a Western coalition. That requires the permission of Berlin, which has so far been hesitant but has lately signaled a willingness to allow it.

Putin launched the invasion on Feb. 24, saying Kyiv's ties with the West threatened Russia's security, and Russia has since claimed to have annexed four Ukrainian provinces. Ukraine and its allies call it an unprovoked war to seize territory, and Kyiv says it will fight until it recaptures all its land.