Ukraine's forces hold defence along the frontline in Donetsk, including of the besieged town of Bakhmut, with the fiercest battles raging for the cities of Vuhledar and Maryinka, Kyiv's top military commander said on Saturday.
Valeriy Zaluzhnyi, commander-in-chief of Ukraine's Armed Forces, said Russia carries out some 50 attacks daily in Donetsk, a region in Ukraine's southeast that Moscow has been trying to occupy fully.
"Fierce fighting continues in the area of Vuhledar and Maryinka," Zaluzhnyi said in a Telegram message after a call with U.S. General Mark Milley.
"We reliably hold the defense. In some areas of the front we have managed to regain previously lost positions and gained a foothold."
Zaluzhnyi did not specify where the gains were. He added that Ukraine continues to hold Bakhmut, trying to "stabilize" the frontline around the town.
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The head of Russia's Wagner mercenary group said on Saturday that his forces are facing fierce resistance around Bakhmut from Ukrainian defenders.
On Friday, Britain said Russian forces were making gains north of Bakhmut, but were having a more difficult time attacking Vuhledar, some 150 kilometers (93 miles) further south.
It is impossible to independently establish the control areas of each side, as fighting along the frontline has slowed in recent months to what Ukraine's defense ministry calls "crawling" attempts to move little by little.
Ukraine's military analyst Oleh Zhdanov said that despite Russia's pressure in Maryinka, a nearly deserted and destroyed small city that has been on the frontline since the start of the war a year ago, Ukrainian forces managed to hold the ground.
"Fighting is going on in the city center, but there have been no changes over the past 24 hours," Zhdanov said in a social media video.
Wagner's head, Yevgeny Prigozhin, said it could take two years for Moscow to control the whole of the Donetsk and Luhansk regions in Ukraine. Moscow last year claimed both as "republics" of Russia, in a move condemned by most countries of the United Nations as illegal.
President Volodymyr Zelenskiy and other military officials have been on a diplomatic marathon in recent months trying to secure more Western weapons and fighter aircraft.
"The key to success on the battlefield is effective fire damage, which requires an appropriate amount of weapons and ammunition," Zaluzhnyi said.