Russia bombarded Ukraine with hundreds of drones and dozens of missiles in a large-scale overnight attack, officials said Friday, killing at least four people. For only the second time, it used a new ballistic missile that it says flies at 10 times the speed of sound and is unstoppable.

The intense barrage and the launching of the nuclear-capable Oreshnik missile came days after Ukraine and its allies reported major progress toward agreeing on how to defend the country from further Moscow aggression if a peace deal is struck to end Russia's almost 4-year-old invasion.

Months of U.S.-led peace efforts have failed to stop the fighting, however. Ukrainian President Volodymyr Zelenskyy says he has made significant progress on the terms of a possible peace settlement in talks with Washington envoys. But Moscow has given no public signal it is willing to budge from its demands.

The attack also coincides with a new chill in relations between Moscow and Washington after Russia condemned the U.S. seizure of an oil tanker in the North Atlantic. It comes as President Donald Trump has signaled he is on board with a hard-hitting sanctions package meant to economically cripple Moscow.

Ukrainian officials said four people were killed and at least 25 wounded in the Ukrainian capital, Kyiv, during the overnight attack as apartment buildings were struck.

Those killed included an emergency medical aid worker, according to Kyiv City Military Administration head Tymur Tkachenko. Four doctors and one police officer sustained injuries while responding to the ongoing attacks, authorities said.

About half of snowy Kyiv's apartment buildings — nearly 6,000 — were left without heating, Mayor Vitali Klitschko said. The water supply was also disrupted.

Municipal services restored power and heating to public facilities, including hospitals and maternity wards, using mobile boiler units, he said

The attack damaged the Qatari Embassy in Kyiv, according to Zelenskyy. He noted that Qatar has played a key role in mediating the exchange of prisoners of war.

He called for a "clear response" from the international community, particularly from the United States, which he said Russia takes seriously.

Russia's Defense Ministry said the attack was a retaliation to what Moscow said was a Ukrainian drone strike on Russian President Vladimir Putin's residence last month. Both Ukraine and Trump have rejected the Russian claim of the attack on Putin's residence.

Putin has previously said that the Oreshnik streaks to its target at Mach 10, "like a meteorite," and has claimed it is immune to any missile defense system. Several of them used in a conventional strike could be as devastating as a nuclear attack, according to Putin, who has warned the West that Russia could use the Oreshnik next against allies of Kyiv that allow it to strike inside Russia with their longer-range missiles.

Ukrainian intelligence says the missile has six warheads, each carrying six submunitions.

Russia didn't say where Oreshnik hit, but Russian media and military bloggers said it targeted a huge underground natural gas storage facility in Ukraine's western Lviv region. Western military aid flows to Ukraine from a big supply hub in Poland just across the border from Lviv.

Russia first used the Oreshnik missile on the Ukrainian city of Dnipro in November 2024. Analysts say it affords Russia a new element of psychological warfare, unnerving Ukrainians and scaring Western countries that supply weaponry to Ukraine.

Ukrainian Foreign Minister Andrii Sybiha said Ukraine would be initiating international action in response to the use of the missile, including an urgent meeting of the UN Security Council and a meeting of the Ukraine-NATO Council.

"Such a strike close to EU and NATO border is a grave threat to the security on the European continent and a test for the transatlantic community. We demand strong responses to Russia's reckless actions," he said in a post on X.

Pope Leo XIV, speaking at the Vatican on Friday, urged the international community to keep pushing for peace and end the suffering in Ukraine.

"Faced with this tragic situation, the Holy See strongly reiterates the pressing need for an immediate ceasefire, and for dialogue motivated by a sincere search for ways leading to peace," the pontiff told ambassadors to the Vatican from around the world.

Lviv Mayor Andrii Sadovyi said that Russia struck critical infrastructure with a ballistic missile, but didn't give details. He said the missile traveled at a speed of 13,000 kilometers (more than 8,000 miles) per hour — which would be around Mach 10 — and that the specific type of rocket was being investigated.

In Kyiv, several districts were hit in the attack, according to Tkachenko, the city's military administration chief. In the Desnyanskyi district a drone crashed onto the roof of a multistory building. At another address in the same district the first two floors of a residential building were damaged.

In Dnipro district, parts of a drone damaged a multistory building and a fire broke out.

Dmytro Karpenko's windows were shattered in the attack on Kyiv. When he saw that his neighbor's house was on fire, he rushed out to help him.

"What Russia is doing, of course, shows that they do not want peace. But people really want peace, people are suffering, people are dying," the 45-year old said.

The attack took place just hours after Zelenskyy alerted the nation about Russia's intentions for a large-scale offensive. He said that Russia aimed to take advantage of the frigid weather in the capital that has made roads and streets perilously icy.