"The Russians’ spring and summer campaign has effectively been disrupted,” Oleksandr Syrskyi told reporters, as cited by the Reuters news agency.
Western analysts say Russia has made only incremental gains along the front line in recent months.
Ukraine says those gains have come at a high human cost, its estimates putting Russian killed and wounded at more than 1.1 million since the start of the war.
Syrskyi said the active front line now stretches 1,250 kilometres, with about 712,000 Russian personnel engaged in the fighting.
He said Russian plans to establish a “buffer zone” in Sumy and Kharkiv in the north and northeast, to seize the city of Pokrovsk and to capture all of the Donetsk region had all failed, Reuters reported.
Securing Donetsk is one of Russia’s war goals; it currently controls more than 70 percent of the region, according to Reuters.
Syrskyi also said that in the past two months, Ukrainian forces had struck 85 military and defence industry targets inside Russia, including air bases, depots and factories, Ukrainian state news agency Ukrinform reported.
The comments came as US President Donald Trump abruptly shifted tone on the war this week.
After previously arguing that Ukraine had no "cards" to play, he said Kyiv could still retake all of the territory lost since Russia’s full-scale invasion—about 20 percent of the country.
He offered no new military aid, however, and instead pressed European allies to shoulder more of the burden, Reuters reported.
Russia launched a full-scale invasion of Ukraine on February 24, 2022, starting the largest military conflict in Europe since World War II.
Friday is day 1,310 of Russia’s war on Ukraine.
(gs)
Source: Reuters, Ukrinform/ukrinform.net