Ukrainian President Volodymyr Zelenskyy has vowed to retaliate after a Russian missile strike on northern Ukraine's Chernihiv killed seven people and wounded 148, an attack

The regional governor confirmed the death toll Sunday, in what the United Nations has denounced as a "heinous" attack.

The strike came during the Orthodox holiday of the Transfiguration of the Lord on Saturday, as some attended morning church services in the city.

In an early-morning update Sunday, Vyacheslav Chaus, governor of Chernihiv region, said there were "seven people dead, 148 people received injuries."

"41 people remain in hospitals. 15 people underwent surgeries," he said in a post on Telegram, adding that "more than 500 homes suffered damage."

The strike hit the center of the city, which is 150 kilometers (90 miles) north of Kyiv toward Belarus, and which had largely been spared from major attacks since the first months of Russia's invasion as fierce fighting rages in the east and south.

The Russian army marched through the city when it invaded Ukraine through Belarus in February 2022, before being repelled by Kyiv's forces.

President Volodymyr Zelenskyy earlier said the dead included "a girl, her name was Sofia, she was 6 years old", and that there were 15 children among the wounded.

"Our soldiers will respond to Russia for this terrorist attack – a tangible answer," he vowed.

From a hospital bed, her legs still covered in blood, Diana Kazakova said she had been inside a shop when the strike happened just minutes after sirens sounded.

When she came to, she said, "people were crying, shouting" in the street outside. "It was scary."

Iryna, a 24-year-old bartender in Chernihiv, told Agence France-Presse (AFP): "There was smoke, screams, people were running, crying, moaning. We ran to the shelter when everything happened and sat there."

UN condemnation

Denise Brown, the U.N.'s humanitarian coordinator for Ukraine, said it was "heinous to attack the main square of a large city, in the morning, while people are out walking, some going to church to celebrate a religious day for many Ukrainians".

"I condemn this repeated pattern of Russian strikes on populated areas of Ukraine ... Attacks directed against civilians or civilian objects are strictly prohibited under international humanitarian law," she added.

Audrey Azoulay, director general of the U.N.'s cultural organization UNESCO, said she was "appalled" by the attack, in a post on social media.

Ukraine's culture ministry said the center of Chernihiv, a city with a thousand-year history, is a candidate for nomination to the UNESCO World Heritage List.

Zelenskyy was in Sweden for talks with Prime Minister Ulf Kristersson, where he finalized "the production of CV90 (armored vehicles) in our country."

"Everything powerful that serves us now, we must localize and produce. We will do so."

They also discussed Ukrainian pilots participating in test trials of Swedish Gripen fighter jets, he said in his evening address.

Putin hosts military top brass

The Kremlin said Russian President Vladimir Putin had traveled to the southern city of Rostov-on-Don, Moscow's hub for its operations in Ukraine, to meet his top generals in a rare trip close to combat zones.

Moscow gave no details of when the meeting took place, but footage released by state media indicated it was at night.

Putin listened to briefings by the Chief of Staff Valery Gerasimov "and other senior officers of the group," the Kremlin said.

A video published by the RIA Novosti news agency showed Putin, wearing a suit, stepping out of a jeep in the dark and being greeted with a handshake by Gerasimov, in military attire.

Rostov-on-Don was also the scene of a dramatic armed mutiny by Wagner mercenaries in June, which saw them briefly take over the army HQ in Rostov, before halting their rebellion.

Gerasimov, who Wagner wanted to unseat, has rarely been seen in public since.

Drone attacks

Kyiv said it had shot down more than a dozen Russian drones in an overnight attack.

A Ukrainian drone attack hit a train station in the western Russian city of Kursk, injuring five people, the regional governor said early Sunday, while in Moscow the mayor said "an attempt was made to fly a drone to Moscow on the southern direction."

"It was thwarted by the air defense forces," he added.

State-run news agency TASS reported that the capital's Domodedovo and Vnukovo airports were temporarily closed.

Vnukovo has faced occasional brief late-night closures over the past few months, when there have been drone attacks nearby.

Both sides have reported regular drone incursions as Ukraine presses a counteroffensive to reclaim Russian-held territory.

Russia's army also said it had "eliminated" 150 Ukrainian troops that tried to cross the Dnipro River into Russian-occupied territory in southern Ukraine, a day after admitting sabotage groups were operating in the area.