Ukrainian President Volodymyr Zelensky used the anniversary to accuse Moscow of endangering global nuclear safety, saying repeated Russian drone operations near the Chernobyl nuclear power plant risked triggering another man-made catastrophe.

“Russia is once again bringing the world to the brink of a man-made disaster,” Zelensky wrote on social media, referring to Iranian-designed Shahed drones used extensively by Russian forces since the full-scale invasion began in February 2022.

He said such drones had repeatedly flown over the plant and that one had struck the protective confinement structure last year, calling for stronger international pressure to halt what he described as “nuclear terrorism.”Russian missile and drone strikes on the southeastern Ukrainian city of Dnipro killed at least nine people, regional officials said, making it the deadliest single attack reported during the latest wave of cross-border strikes.

In Russian-occupied Crimea, Moscow-installed authorities said one man was killed in a Ukrainian drone strike on the port city of Sevastopol. Russia annexed Crimea from Ukraine in 2014, a move widely rejected by the international community, and has since used the peninsula as a key military logistics hub.

In eastern Ukraine’s occupied Luhansk region, Leonid Pasechnik, the Russia-backed governor, said three people were killed in an overnight Ukrainian drone strike on a village, after earlier reporting two deaths on Saturday.Earlier, authorities in Russia’s Belgorod border region said a woman was killed in a Ukrainian drone attack.

Ukraine did not publicly comment on the strikes in Crimea or Luhansk, and the claims could not be independently verified.Ukraine’s military said it had also struck an oil refinery in Yaroslavl, deep inside Russian territory, triggering fires at a facility that processes around 15 million tons of oil annually and produces gasoline, diesel and jet fuel, including supplies for the Russian military.Russia did not immediately comment on the refinery attack.

Kyiv has increasingly used domestically developed long-range drones capable of reaching targets up to 1,500 km (900 miles) inside Russia, targeting energy infrastructure and military logistics sites.Ukrainian officials argue such strikes are aimed at reducing Russian military capacity, particularly as Moscow seeks to increase oil exports after the Trump administration granted temporary sanctions waivers to ease global supply constraints.

The anniversary of the 1986 Chernobyl disaster also renewed focus on the safety of the damaged reactor site.Rafael Grossi, director general of the International Atomic Energy Agency, said repairs to the plant’s outer protective shell must begin urgently after damage from a strike last year compromised a key safety function of the structure.

He warned that prolonged delays could increase risks to the original sarcophagus covering Reactor No. 4, the site of the world’s worst nuclear disaster.The European Bank for Reconstruction and Development estimated repairs would require at least 500 million euros ($586 million).

Ukraine’s Energy Minister Denys Shmyhal said international partners had so far committed 100 million euros in additional funding, on top of a previously agreed 30 million euros.Ukrainian officials say a Russian drone struck the outer shell of the New Safe Confinement structure in February 2025.

The $2.1 billion steel arch, completed in 2019, was built to contain radioactive material over the destroyed reactor.Moscow denied responsibility and accused Kyiv of staging the incident.Separately, Russia’s Defense Minister Andrei Belousov visited North Korea on Sunday for talks with leader Kim Jong Un, where both sides discussed expanding military cooperation.

Belousov said the two countries had agreed to move military ties to a “sustainable, long-term basis,” according to Russian state news agency RIA Novosti.During the visit, he awarded Russia’s Order of Courage to North Korean troops who served in Russia’s Kursk region, where Ukrainian forces launched a surprise incursion in August 2024.

Kim has supplied thousands of troops and significant weapons shipments to support Russia’s war effort.

The commemoration comes as Kyiv accuses Moscow of repeatedly sending missiles and drones along flight paths near the former Chernobyl Nuclear Power Plant while attacking Ukrainian cities, including a February 2025 drone strike that damaged the plant’s protective confinement structure.

Ukraine’s Foreign Ministry said the original 1986 catastrophe was caused by a reactor experiment ordered by Soviet authorities in Moscow in violation of safety rules and followed by concealment of the scale of the disaster.

“The Chernobyl disaster was the result of a reactor experiment ordered by Moscow, in violation of safety protocols, and followed by lies and cover-ups,” the ministry said in a statement this week.

Millions of people across Europe were exposed to radiation after reactor four exploded during a late-night safety test on April 26, 1986, sending radioactive material across large parts of the continent.

Hundreds of thousands were evacuated, while vast agricultural and residential areas were rendered unsafe for habitation.Thousands later developed radiation-related illnesses, including cancer, though the total death toll remains disputed among researchers and international agencies.

A major international engineering effort led to the installation in 2016 of a vast steel and concrete confinement arch over the original sarcophagus hastily built after the explosion to contain radioactive debris.

That structure, designed to prevent further contamination, was punctured during a Russian drone strike in February 2025, Ukrainian officials said.

While no radiation leaks were detected, the European Bank for Reconstruction and Development estimates repairs will require at least 500 million euros to prevent lasting damage.

Earlier this week, Ukraine’s top state prosecutor told that radar systems had detected at least 92 Russian drones flying within five kilometers of the protective shield since June 2024, raising renewed international concern over the safety of the site.

Russia has denied accusations of deliberately endangering nuclear facilities during the war, while previous disputes over attacks near energy infrastructure have intensified fears of a broader nuclear emergency.

Located about 100 kilometers north of Kyiv, the plant remains inside a 2,600-square-kilometer exclusion zone established after the disaster. Around 2,250 employees continue to work in rotating shifts to oversee the long-term decommissioning of the site.

The plant’s final operational reactor was shut down in 2000.The control room of reactor four now stands dark and rusted, filled with damaged Soviet-era machinery left as a reminder of the explosion.Outside, wildlife including moose and wild horses roam through the abandoned forests and the nearby ghost city of Pripyat, where nature has reclaimed neighborhoods once evacuated in haste.

Security concerns continue to shape official remembrance ceremonies in wartime Ukraine, with authorities typically withholding details of commemorations in advance to reduce risks from missile and drone attacks.

For many Ukrainians, the anniversary now serves not only as a memorial to a Soviet-era catastrophe, but also as a warning of how war can once again place Europe’s nuclear safety at risk.