Ukraine and Russia have continued striking each other overnight, with President Volodymyr Zelensky accusing Moscow of using North Korean missiles.
Ukraine said strikes on the southern city of Zaporizhzhia – which killed seven people and injured at least 24 – involved ballistic missiles from Russia's ally.
In Voronezh, western Russia, warehouses of the biggest online retailer Wildberries were hit by Ukraine. The company, known as Russia's Amazon, has been repeatedly targeted in recent weeks.
The attacks come a day after at least 13 people were killed, including one child, in Ukrainian drone strikes on the Russian republic of Tatarstan, more than 1,100 km (680 miles) from the Ukrainian border.
In a video address on Monday evening, Zelensky said "for the first time" Russia "cannot wage war without reinforcements from North Korea".
"The more North Korean strikes there are here in Ukraine, in Europe, the more their missiles and soldiers are used, the more they correct their shortcomings and blind spots", Zelensky said, adding that this poses a danger to the rest of the world.
He has not presented any evidence to back up his comments.
It is not the first time Zelensky as well as other senior Ukrainian and Western officials have accused Russia of receiving military assistance from North Korea.
Ukraine's military has said that says dozens of North Korean missiles have been fired by Russia into its territory since Moscow's full-scale invasion in February 2022.
The Ukrainian president warned over the weekend that as many as 50,000 North Korean soldiers were being sent to fight with Russian forces.
Some 11,000 North Korean soldiers were deployed to help Moscow push Ukrainian troops out of the western Russian region of Kursk following their cross-border incursion in August 2024.
In January 2025, Western officials told the BBC that North Korean troops had suffered nearly 40% casualties in the fighting there in just three months.
In his Monday's address, Zelensky also hailed a successful air strike on a Russian petrochemical plant in western Siberia on Monday as a "very significant achievement" by the Ukrainian military.
He promised "more Ukrainian deep strikes, which should demonstrate to Russia and the Russians that peace is necessary".
Zaporizhzhia regional head Ivan Fedorov posted photos of vehicles and buildings on fire, saying Moscow had struck the city using missiles and guided bombs.