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.

Four contenders are competing for the post, with the successful candidate set to assume office at the start of next year and confront mounting challenges facing the United Nations, whose global standing has come under increasing scrutiny.

During two days of hearings, candidates emphasized the need to modernize the 80-year-old body, established after World War Two, as geopolitical tensions and actions by major powers strain the norms underpinning the post-war international order.

Rebeca Grynspan, former vice president of Costa Rica and current head of the United Nations Conference on Trade and Development, said restoring trust in the institution would be critical, identifying peacemaking as her top priority.

“To defend the United Nations today is to have the courage to change it,” Grynspan said, warning that confidence in the organization was eroding and time to reverse the trend was limited.

Macky Sall, who served as Senegal’s president until 2024, advocated what he described as “rigorous management” reforms aimed at improving coordination across UN agencies and reducing duplication, as pressure mounts to cut costs and demonstrate effectiveness.

“Now is the time to do better with less,” Sall said, outlining his vision for a more efficient and forward-looking institution.The candidates are vying for a five-year term, renewable once, in a process that has drawn fewer applicants compared to 2016, when Guterres was selected from a field of 13 contenders.

Grynspan and Michelle Bachelet are seeking to become the first woman to lead the United Nations, reflecting a broader push for gender representation at the highest levels of global governance.

Bachelet reiterated her support for women’s rights during her hearing, amid opposition from some conservative U.S. lawmakers over her stance on abortion.Also in the race is Rafael Grossi, a career diplomat from Argentina who currently heads the International Atomic Energy Agency.

Grossi said reform efforts were progressing but remained incomplete.While there is no formal requirement, longstanding precedent discourages candidates from the five permanent members of the United Nations Security Council Britain, China, France, Russia and the United States to avoid concentration of power, although their support remains decisive in the selection process.