(Reuters) -Ukraine's President Volodymyr Zelenskiy said on Thursday that Ukrainian forces were gradually pushing Russian forces out of the border Sumy region, where Moscow has established a foothold in recent weeks.
Russian forces have been moving into Sumy region since April when Kremlin leader Vladimir Putin called for the creation of a buffer zone after he said all Ukrainian troops had been evicted from a months-long incursion into Russia's western Kursk region.
Both Russian and Ukrainian reports indicate that Russian forces have seized a series of villages in the region, which has for many months also come under heavy Russian air attacks. And Russian reports said Moscow's troops were advancing in the area.
"Our units in Sumy region are gradually pushing back the occupiers," Zelenskiy said in his nightly video address. "I thank you! Thanks to every soldier, sergeant and officer for this result."
The Ukrainian president provided no further details and offered no proof of Ukrainian advances in the area.
Ukrainian presidential adviser Mykhailo Podolyak said there had been a concentration of Russian men and equipment in Sumy region because of months of military operations across the border in Kursk region. He advised caution to establish details of the situation on the ground.
"I think (Ukraine's) military has the situation under control and I think we shall see a different picture in the coming days," Podolyak told Ukrainian TV Channel 24.
The popular Ukrainian military blog DeepState, which charts the position of Russian troops using open-source materials, reported Russian gains in recent days around villages inside the border.
Other Ukrainian bloggers said on Thursday that Russian forces had advanced to within 20 km (12 miles) of the city of Sumy and were likely to move southward on villages to secure high ground outside the city.
Russian media reported similar advances through the region. One military site "Voyennoe Obozrenie" said Russian forces had made "significant progress" and were now positioned south of a major highway.
(Reporting by Ron Popeski and Bogdan KochubeyEditing by Marguerita Choy)
