In a statement, the Ministry of Defence of the Russian Federation said Ukrainian forces continued attacks using drones and artillery despite the temporary truce announced by Russia.

“Despite the declaration of a ceasefire, Ukrainian armed groups continued to launch attacks using drones and artillery against the positions of our troops, as well as against civilian targets in the border areas of the Belgorod and Kursk regions,” the ministry said.

“Despite the declaration of a ceasefire, Ukrainian armed groups continued to launch attacks using drones and artillery against the positions of our troops, as well as against civilian targets in the border areas of the Belgorod and Kursk regions,” the ministry said.

The ministry said Russian forces responded “in kind” to the alleged violations, carrying out strikes against artillery systems, mortar positions, command centers and drone launch sites operated by Ukrainian forces.

The ceasefire had been announced by Moscow to coincide with ceremonies commemorating the Soviet victory over Nazi Germany, one of Russia’s most symbolically important national observances.The statement did not specify the scale of the reported attacks or provide casualty figures.

Border regions including Belgorod and Kursk have faced repeated drone strikes and shelling during the conflict, which began with Russia’s full-scale invasion of Ukraine in February 2022.

Kyiv has previously questioned the sincerity of temporary Russian ceasefire announcements, accusing Moscow of continuing military operations during declared pauses in fighting.

Neither side’s battlefield claims could be independently verified.

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.