Zelenskiy told a conference in Kyiv that Russia's counterattack in the Kursk region had also had no major successes - contradicting President Vladimir Putin's accounts of Russian advances on both fronts.
Ukraine launched a surprise incursion in the Kursk region on August 6, pushing into the Russian territory and claiming control over dozens of settlements.
"It gave the results that, frankly speaking, we counted on. In the Kharkiv region, the enemy was stopped. Their advance in the Donetsk region was slowed down although it is very difficult there," Zelenskiy said.
Russian forces say they have retaken 10 villages out of 100 seized by Ukraine in Kursk. (AP PHOTO)
Zelenskiy said that Russia had about 40,000 troops on the Kursk front, and those had begun a counterattack.
"So far we have seen no serious (Russian) success," he added, during his most comprehensive public comments on the situation since the launch of the Kursk operation.
Russia's defence ministry said on Friday its troops had taken back 10 villages out of 100 that Ukraine had claimed.
Reuters has not been able to verify battlefield reports from either side independently.
More than two and a half years since Russia's full-scale invasion, the war is at a critical juncture, with Russian forces regularly pounding Ukrainian infrastructure and cities as its troops try to push back Ukraine's incursion and complete the capture of the whole of Ukraine's eastern Donbas region.
I will soon meet President Biden, where I will present him the Victory Package – a system of interconnected decisions that will provide Ukraine with the necessary strength to set the course toward peace. Wars of aggression such as Russia's war against Ukraine end in one of two…— Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) September 13, 2024
Zelenskiy acknowledged that the situation near the logistics hub of Pokrovsk in Ukraine's eastern Donetsk region remained difficult although he said that had stabilised over the past week.
Ukraine's General Staff reported on Friday that Russian forces focused their assaults near the town of Kurakhove, about 33km south of Pokrovsk.
Ukrainian forces are stretched thin in the eastern Donetsk region but the military said they had repelled 64 assaults near Kurakhove in the past day, the most intense fighting there so far this month.
An additional 36 Russian assaults had been repelled near Pokrovsk, it added.
Zelenskiy has earlier described the Kursk operation as a part of his broader "victory plan" he aims to present to US President Joe Biden later this month.
"(The plan) can pave the way for a reliable peace - for the full implementation of the peace formula," Zelenskiy said on Friday.
He declined to disclose the details of the plan but said it consisted of a small number of points.
"And all these points depend on Biden's decision. Not Putin's," Zelenskiy added.
Ukraine has stepped up calls on its allies, in particular the United States, to allow long-range attacks into Russia, saying it is critical for its efforts to restrict Russia's ability to attack Ukraine.
Allies have so far been reluctant to permit such strikes, citing fears Russia will treat this as an escalation.
Ukraine received 49 prisoners of war back from Russia in the latest exchange of captives between the warring neighbours, Zelenskiy said on Friday.
"These are fighters from the armed forces of Ukraine, the National Guard, the police, the Border Guard Service and also our civilians," Zelensky wrote on Telegram.
Some of the group were taken prisoner during the defence of the Azovstal steelworks in the southeastern Ukrainian city of Mariupol at the start of the war in 2022.
There were 23 women among those released, the Ukrainian president said.
How many prisoners were handed over to Russia was not disclosed.
However, the co-ordination staff for matters relating to prisoners of war cited an exchange.
There was initially no information from the Russian side.
According to Ukrainian figures, Russia and Ukraine have exchanged prisoners 56 times in the last two and a half years.
A total of 3569 Ukrainians have been released by Russia to the Ukrainian side.
with DPA
