The Ukrainian army said Sunday that it has pushed Russian forces back "three to eight kilometres" from the banks of Dnipro river, which if confirmed would be the first meaningful advance by Kyiv's forces months into a disappointing counteroffensive.

"Preliminary figures vary from three to eight kilometres, depending on the specifics, geography and landscape design of the left bank," army spokeswoman Natalia Gumenyuk told Ukrainian television, without specifying whether Ukraine's military had complete control of the area or if the Russians had retreated.

"The enemy still continues artillery fire on the right bank," she said, estimating that "several tens of thousands" of Russian troops are in the area.

"We have a lot of work to do," she added.

Ukrainian and Russian forces have been entrenched on opposite sides of the vast waterway in the southern Kherson region for more than a year, after Russia withdrew its troops from the western bank last November.

Ukrainian forces have staged multiple attempts to cross and hold positions on the Russian-controlled side -- with officials in Kyiv finally reporting a "successful" breakthrough last week.

It comes after Kyiv's much-awaited counteroffensive launched last June had largely fizzled, with Ukraine retaking just a handful of villages in the south and east.

The last significant success claimed by Kyiv was the retaking in August of the village of Robotyne in the southern region of Zaporizhzhia.

Ukrainian forces were not able to further pierce Russia's defensive lines.

A bridgehead on the left bank of the Dnipro would allow a deeper offensive in the south, though it would require deploying more men and armour in the difficult-to-reach marshy region.

AFP has not able to independently confirm the claims made by officials.