North Korean leader Kim Jong-un has hailed the troops from his country who fought alongside Russia in Kursk a year ago, state media KCNA said on Monday. Kim made his remarks after a Russian delegation arrived in Pyongyang to attend the opening ceremony of a memorial complex honouring those killed helping Moscow’s invasion of Ukraine. In 2024 Ukraine launched a surprise incursion into the Kursk region, capturing more than 1,000 sq km (386 sq miles) of Russian land, but were ultimately pushed back.

During discussions in Pyongyang, Russia and North Korea agreed to “long-term” military cooperation. Moscow’s defence minister Andrey Belousov said “We agreed with the DPRK defence ministry to place our military cooperation on a stable, long-term footing,” The agreement will cover 2027-2031, he said. North Korea has sent thousands of troops – as well as missiles and munitions – to support Russia’s war in Ukraine. In return, analysts say North Korea is receiving financial aid, military technology, food and energy from Russia.

Kim said his government “would continue to fully support Russia’s policies of defending its sovereignty, territorial integrity and security interests”, KCNA reported. Kim has steadily moved to elevate the North Korean troops who fought for Russia in the Kursk region into symbols of sacrifice and loyalty, using state ceremonies and memorial projects to publicly honour their role. “The souls of the fallen will live forever with the great honour they defended,” Kim said in a handwritten message at the memorial on Sunday, according to state media.

Meanwhile, strikes across Ukraine, Russian-occupied territory and Russia over the past day killed at least 16 people, authorities said. Russian drone and missile strikes on the city of Dnipro killed at least nine, regional head Oleksandr Hanzha said. One man was killed in a Ukrainian drone strike on the port city of Sevastopol, in Russian-occupied Crimea, Moscow-installed authorities said.

Ukrainian president Volodymyr Zelenskyy accused Russia of “nuclear terrorism” as he marked the 40th anniversary of the Chornobyl reactor disaster on Sunday. Zelensky said Russia was “again bringing the world to the brink of a man-made disaster”. He said Russian drones regularly pass over Chornobyl and one had hit its protective shell last year.

Rafael Grossi, director general of the International Atomic Energy Agency (IAEA), echoed Zelenskyy’s concerns over Chornobyl during a visit to Kyiv, saying repairs to the plant’s damaged outer protective shell must begin immediately. IAEA assessments show the damage sustained after a strike last year has already compromised a key safety function of the structure, he said. He warned years of inaction could heighten danger to the original sarcophagus beneath it. The European Bank for Reconstruction and Development said repairs would require at least 500 million euros ($586m).

Ukrainian forces struck an oil refinery in Yaroslavl, deep inside Russian territory, Ukraine’s General Staff said on Sunday. The strikes sparked fires at the facility, which processes 15m tons of oil a year and produces gasoline, diesel and jet fuel for the Russian military. Russia did not immediately comment. Ukraine has developed its own long-range drones, which can reach targets 1,500km (900 miles) inside Russia.

A Ukrainian drone attack also hit a fertiliser plant in Russia’s Vologda region, local governor Georgy Filimonov said on Sunday. Filimonov said a high-pressure sulphuric acid pipeline was damaged at a complex operated by Apatit, a subsidiary of PhosAgro, one of the world’s largest producers of phosphate-based fertilisers. The leak has been contained and there were no releases of hazardous chemicals, he said, adding that five people were injured.

Donald Trump said on Sunday he has had “good conversations” with Vladimir Putin and Zelenskyy as he aims to settle the Ukraine war. “We’re working on the Russia situation, Russia and Ukraine, and hopefully we’re going to get it,” Trump said in an interview on Fox News. Ukrainian peace talks have stalled since the US and Israel launched attacks on Iran on 28 February.