Russian President Vladimir Putin said Friday that a long-expected counter-offensive from Ukraine had begun but Kyiv had so far "failed" to reach its goals.
"We can definitely state that this Ukrainian offensive has begun," Putin said in a video interview published on Telegram by a Russian journalist.
"But the Ukrainian troops did not reach their aims in any area of combat," he added.
Ukraine has for months said it was preparing a counter-offensive to repel Russian troops from its territories, but said there would be no formal announcement.
Putin said that "combat has continued for five days, with intense fighting yesterday and the day before."
He said Ukrainian forces had suffered "significant losses" but "the offensive potential of the Kyiv regime still remains."
For several days, the Russian army has said it repelled assaults in the south of Ukraine, which would be the opening phase of Kyiv's offensive.
Kyiv, however, said the main centre of combat was still in Ukraine's east, while providing few details on the situation in the south.