Late Wednesday, Russia's most senior defense officials responsible for Ukraine announced in a televised meeting that they had taken the "difficult decision" to withdraw from Kherson and set up defensive lines further back.
Ukrainian President Volodymyr Zelensky has suggested Russia could be strategically feigning rather than experiencing a major setback.
Military officials in Kyiv reiterated that caution on Thursday.
"At this point, we can't confirm or deny information about the retreat of Russian troops from Kherson," said Oleksiy Gromov, from the Ukrainian armed forces' general staff.
Ukrainian officials have remained wary since Moscow first signaled late Wednesday that it was pulling forces from the west bank of the Dnipro river in Kherson, in what would be major Russian setback in a region Vladimir Putin claimed to have annexed.
Ukrainian general Valeriy Zaluzhny said on social media that Ukraine's forces had recaptured six settlements after fighting near the Petropavlivka-Novoraisk front.
Kyiv's army had taken another six in the Pervomaiske-Kherson direction, capturing a total of more than 200 square kilometers from the Russians, he added.
"The Russian troop units are maneuvering to prepared position on the left bank of the Dnipro river in strict accordance with the approved plan," the Russian defense ministry said.
In the nearby southern city of Mykolaiv, which Russian forces have pounded with artillery and missiles for months, there was little belief the Russians would do as they said.
"You cannot trust what they say. No one will give us anything back just like that," Svitlana Kyrychenko, a 54-year-old store clerk, told AFP.
Russia losing the Kherson region would return to Ukraine important access to the Sea of Azov and leave Putin with little to show from a campaign that has turned him into a pariah in Western eyes.
The retreat will put pressure on Russian control of the rest of the Kherson region, which forms a land bridge from Russia to Crimea, the peninsula that Moscow annexed in 2014.
Kherson was one of four Ukrainian regions that Russia declared it had annexed in September, shortly after being forced to withdraw from swathes of territory in the northeastern Kharkiv region.