Ukrainian forces were on Monday said to have recaptured towns along the west bank of the Dnieper River in southern Ukraine near the city of Kherson.
Moscow's troops have yielded land that Russia claims to have annexed along a second major front. The news comes days after Ukrainian forces took the key logistics hub of Lyman — Kyiv's most significant battlefield gain in weeks.
What do we know so far?
While there has been official confirmation of the gains from Kyiv, Russian sources acknowledged that a Ukrainian tank offensive had penetrated dozens of kilometers along the river's west bank. Several villages along the way were said to have been recaptured.
Russian Defense Ministry spokesman Igor Konashenkov said that "with superior tank units in the direction of Zolotaya Balka, Aleksandrovka, the enemy managed to penetrate into the depths of our defense."
However, he added that Russian troops "have occupied a pre-prepared defensive line and continue to inflict massive fire damage" on the Ukrainian forces.
"The information is tense, let's put it that way, because, yes there were indeed breakthroughs," Vladimir Saldo, the Russian-installed leader in Kherson province told Russian state television.
"There's a settlement called Dudchany, right along the Dnieper River, and right there, in that region, there was a breakthrough. There are settlements that are occupied by Ukrainian forces," he said.
Russian military bloggers have described a Ukrainian tank advance through dozens of kilometers of territory along the Dnieper's western bank.
Rob Lee, a senior fellow at the Foreign Policy Research Institute think-tank, cited Russian bloggers as reporting that Moscow's troops had retreated as far as Dudchany — 40 kilometers (25 miles) downriver from where they were fighting a day earlier.
"When this many Russian channels are sounding the alarm, it usually means they're in trouble," he wrote on Twitter.
What does the breakthrough mean for the wider war?
The advance in the south mirrors recent successes by Kyiv's forces in the east, which have turned the tide in the war against Russia.
It comes despite Moscow seeking to raise the stakes by illegally annexing territory, ordering a partial mobilization and threatening nuclear retaliation.
Both the Ukrainian military breakthroughs set the stage for advances aimed at further cutting Russian supply lines.
Kherson has been one of the most difficult battlefields for the Ukrainians.
The region is one of four regions illegally annexed by Moscow last week after the rapidly so-called "referendums" that were orchestrated by the Kremlin.
Western nations have slammed the referendums as sham votes, often conducted at gunpoint.
