Ukrainian President Volodymyr Zelenskyy projected optimism despite a stalled counter-offensive on Friday, in a last-minute speech at the annual Aspen Security Forum.
“Ukraine is not backtracking, but progressively liberates its territories,” Mr Zelenskyy said.
“Our intelligence suggests that some of our residential areas have been liberated already. So I do believe in our victory.”
Ukraine has not yet achieved a major breakthrough across Russian lines since the launch of Kyiv's counter-offensive last month.
But Ukrainian forces have recaptured some villages in the south and territory around the ruined city of Bakhmut in the east.
Kyiv claims the slow pace is deliberate to avoid high casualties.
Mr Zelenskyy emphasised the importance of his forces acquiring long-range artillery to strengthen the counter-offensive, saying that progress “depends on the lead of the US and its defence assistance”.
US Gen Mark Milley, Chairman of the Joint Chiefs of Staff, earlier this week said the internationally backed mission “is far from a failure”.
“I think that it's way too early to make that kind of call,” he said.
The Ukrainian President spoke as Moscow continues to bombard Ukrainian Black Sea port cities and after officials in Kyiv announced Russian shelling had killed a young brother and sister.
A Ukrainian official on Friday said that the two children were killed by Russian artillery in the eastern village of Druzhba.
“At about 3pm, the Russians shelled the village with artillery – one of the shells hit the yard where the children were staying – a 10-year-old boy and a 16-year-old girl,” the head of the Donetsk region military administration, Pavlo Kyrylenko, wrote on his Telegram channel.
Tension is also escalating in the Black Sea, with global implications.
Russia on Monday withdrew from a deal that had allowed the safe passage of about 33 million tonnes of food from Ukraine through the Black Sea, about half of it to developing countries.
Moscow said that any ships travelling to Ukraine's Black Sea ports will be suspected of carrying military cargo.
The warning comes after Kyiv said it was setting up a temporary shipping route to try to continue exporting grain.
