KYIV, Ukraine (AP) — Ukrainian President Volodymyr Zelenskyy accused Russia of trying to humiliate the United Nations by raining missiles on Kyiv during a visit to the city by the U.N. chief, an attack that upset weeks of relative calm and a tentative return to normal in the capital.

Ukraine’s forces, meanwhile, fought to hold off Russian attempts to advance in the south and east, Zelenskyy reported. And efforts continued to arrange safe passage for residents trapped in Mariupol, largely reduced to rubble in a 2-month-long siege. An official in the president’s office said an evacuation could happen as soon as Friday.

Russia pounded targets all over Ukraine on Thursday, hitting a residential high-rise and another building in Kyiv. U.S.-funded broadcaster Radio Free Europe/Radio Liberty said one of its journalists was killed.

In an apparent reference to the attack, Russia’s Defense Ministry said it had destroyed “production buildings” at the Artem defense factory in Kyiv.

The bombardment came barely an hour after Zelenskyy held a news conference with U.N. Secretary-General António Guterres, who toured some of the destruction in and around Kyiv and condemned attacks on civilians.

"This says a lot about Russia’s true attitude toward global institutions, about attempts of the Russian leadership to humiliate the U.N. and everything the organization represents,” Zelenskyy said late Thursday in his nightly video address to the nation. “Therefore, it requires a correspondingly powerful response.”

Kyiv Mayor Vitali Klitschko said the attack was Russian President Vladimir Putin's way of giving Guterres “his middle finger.”

The strikes were the boldest Russian attack on the capital since Moscow’s forces retreated weeks ago following their failure to take the city. Russia is now pushing into the Donbas, the country's eastern industrial region, which the Kremlin says is its main objective.

Getting a full picture of the unfolding battle in the east has been difficult because airstrikes and artillery barrages have made it extremely dangerous for reporters to move around. Both Ukraine and the Moscow-backed rebels fighting in the east also have introduced tight restrictions on reporting from the combat zone.

But so far, Russia’s troops and the separatist forces appear to have made only minor gains, and Britain’s Defense Ministry said those have been achieved at significant cost to the Kremlin's forces.

One aim of Guterres' visit was to secure the evacuation of people from the ruined southern port of Mariupol, including a shattered steelworks where an estimated 2,000 Ukrainian defenders and 1,000 civilians were holed up in the last major stronghold of resistance in the city. Previous evacuation attempts fell through.

About 100,000 people are believed trapped in the city with little water, food, heat or electricity.

“I cannot confirm the exact details of the operation to make sure it is done with safety for our people and for civilians stranded in Mariupol” said Saviano Abreu, a spokesperson for the U.N. humanitarian office.

An official in Zelenskyy’s office said negotiations were underway with U.N. mediation.

Two towns in Ukraine's central Dnipropetrovsk region were hit by Russian rockets on Friday, the regional governor said. There was no immediate word on casualties or damage.

The governor of Russia’s Kursk region said that a border post came under mortar fire from Ukraine and that Russian border forces returned fire. He said there were no casualties on the Russian side.

Thursday's explosions in northwestern Kyiv’s Shevchenkivsky district shook the city. Flames poured out the windows of the buildings hit.

Radio Free Europe/Radio Liberty said the body of Vira Hyrych, a journalist who had worked for the broadcaster since 2018 and who lived in one of the buildings, was found in the rubble on Friday.

Radio Free Europe President Jamie Fly said the broadcaster was “shocked and angered by the senseless nature of her death at home in a country and city she loved.”

Ten people were wounded in the attack, including at least one who lost a leg, according to emergency officials.

Kyiv had been relatively unscathed in recent weeks, and cafes and other businesses have started to reopen, while a growing numbers of people have been out and about, enjoying the spring weather.

The terrible human cost of the war, which has driven more than 11 million Ukrainians from their homes, continues to climb.

In Lyman, a town in Donetsk, in the Donbas, shells rained on Tatiana Matsegora’s home this week. Matsegora’s 14-year-old grandson, Igor, was declared dead after rescue workers drove him to the hospital. Her daughter was in serious condition, and her son-in-law was also killed.

"'Grandma, will I live?'" she said Igor asked her when they were in the basement, waiting for help. “I said that he would live. But look what happened: I betrayed him.”

___

This story has been updated to correct that Thursday’s strike on Kyiv was the boldest attack since Moscow’s retreat, not necessarily the first, and also to correct the spelling of the last name of the woman who lost her grandson to Matsegora.

___

Associated Press journalists Jon Gambrell and Yuras Karmanau in Lviv, Mstyslav Chernov in Kharkiv, Yesica Fisch in Sloviansk, and AP staff around the world contributed to this report.

___

Follow AP’s coverage of the war in Ukraine: https://apnews.com/hub/russia-ukraine

Copyright 2022 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.