Moscow stepped up its attacks in the northeastern section of the front line last autumn, seeking to encircle bastions such as the town of Avdiivka. The Ukrainian military said it was in "active defence" while carrying out counterattacks.
"(Russia's) offensive is still ongoing. Somewhere in early spring, it will be exhausted completely," Kyrylo Budanov, head of Ukraine's military intelligence agency GUR, said on national TV.
Budanov played down the Russian forces' gains, saying they had only achieved "a few advances across some fields" and near the embattled town of Avdiivka. "Now it's the enemy's move. It will end, and I think ours will start," he added.
Ukraine's own counteroffensive, launched in June 2023, has not produced any major breakthrough. Ukrainian officials have blamed extensive Russian minefields and defensive lines, and delays in supplies of weapons from the West.
Ukrainian military officials have spoken recently of increased Russian military activity on long stretches of the 1,000-km-long (600-mile) front line through eastern and southern Ukraine.
Russian President Vladimir Putin has repeatedly said his forces will achieve all their aims in what Moscow calls its "special military operation" in Ukraine, now in its 24th month.
Putin says he sent troops into Ukraine to buttress Russia's own security against what he casts as a hostile and aggressive West. Kyiv and its Western allies say this is nonsense and that Moscow is engaged in an unprovoked war of aggression and an imperial-style land grab.
(Reporting by Yuliia Dysa; Editing by Gareth Jones)
