Russian President Vladimir Putin said Ukraine had begun a major offensive against Russia's army but that Ukrainian forces had failed to achieve their objectives despite intense fighting over at least three days.
"We can state for sure that this offensive has begun. This is evidenced by the use of strategic reserves of the Ukrainian army," Putin told Russian reporters in Sochi. "Ukrainian troops did not achieve their goals in any sector."
Putin said fighting had been very intense over the past three days but that "the enemy did not have success" in any of the battles.
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.
