Rescue workers ended search operations at the devastated building, which was struck on Thursday during Russia's heaviest air attack on the Ukrainian capital in 2026.
"Our first responders ... worked non-stop for more than a day," Zelenskiy said on the Telegram app after visiting the site in Kyiv's Darnytskyi district, on the left bank of the Dnipro River, laying flowers and talking to rescue workers.
"The Russians practically levelled an entire section of the building with their missile," he said.
Russia, which began its full-scale invasion of Ukraine in February 2022, had launched more than 1500 drones and dozens of missiles at targets in Ukraine over two consecutive days, according to Ukrainian officials.
Six people were also killed in western Ukraine, far from the front line.
"A Russia like this can never be normalised - a Russia that deliberately destroys lives and hopes to remain unpunished. Pressure is needed," Zelenskiy said, reiterating appeals to allies to help Ukraine strengthen its air defences.
Moscow's defence ministry said its forces had carried out massive strikes on Ukraine on May 12-15, the Russian state news agency RIA reported.
Kyiv officials declared Friday a day of mourning, with national flags at half-mast across the city of three million.
Residents brought flowers, stuffed animals and sweets to a makeshift memorial at the destroyed housing block.
The interior ministry said hundreds of rescuers had sifted through 3000 cubic metres of rubble in 28 hours of searching.
City officials said 24 bodies had been recovered and about 30 people rescued alive.
Nearly 50 people were wounded, and about 400 required psychological support, the ministry said.
Zelenskiy has said initial analysis shows the building was hit by a recently made Russian Kh-101 missile.
Moscow denies deliberately targeting civilians but during more than four years of war it has frequently hit residential buildings and other civilian infrastructure all over Ukraine.
Ukraine has also carried out drone attacks on Russia.
Four people, including a child, were killed in an attack on the central Russian city of Ryazan on Friday that damaged high-rise apartment buildings and hit an unnamed industrial enterprise, the regional governor said.
Ukraine said it had struck a Russian oil refinery in Ryazan.
Russia and Ukraine have continued to occasionally swap prisoners of war, and 205 from each country returned home on Friday.
Zelenskiy said it was the first phase of a planned 1000-for-1000 prisoner swap.
Some of the Ukrainians released had been held in Russian captivity since 2022, he said, and had fought in some of the war's fiercest battles.
Russia's defence ministry confirmed the exchange and thanked the United Arab Emirates for helping broker it.
with AP
