The death toll from Russian strikes on a hardware store in the eastern Ukrainian city of Kharkiv rose to 16 on Sunday, authorities said, as rescuers continued to search the charred debris for bodies. The dead included a 12-year-old girl. Another 43 people were wounded and several people were listed as missing.

Ukraine’s president, Volodymyr Zelenskiy, released a desperate video plea calling on world leaders to attend a “peace summit” in Switzerland. Zelenskiy appealed in particular to the US president, Joe Biden, and the Chinese leader, Xi Jinping, to attend the summit, which is due to start on 15 June. “Please, show your leadership in advancing the peace – the real peace and not just a pause between the strikes,” said Zelenskiy in English. Biden has not yet confirmed his attendance and it is not known whether China will attend – “negotiations are ongoing” over Beijing’s participation, Zelenskiy’s aide Mykhailo Podolyak said in an interview last week.

Zelenskiy is set to meet Spanish prime minister Pedro Sánchez in Madrid on Monday, as well as King Felipe VI. Earlier this month, Zelenskiy postponed all upcoming foreign visits, including the trip to Spain that had been scheduled for 17 May, after Russia launched an offensive in the north of the Kharkiv region.

Ukrainian prosecutors said Russian shelling on Sunday killed three people in three different towns in the Donetsk region, another focal point for the Russian military’s onslaught. Prosecutors in Donetsk region, which Russia has annexed though it does not control all of its territory, said civilians had died in Siversk in the north of the region and further south in Krasnohorivka and Chasiv Yar.

Russian forces have also taken over the village of Berestove in Ukraine’s northeastern Kharkiv region, the Tass news agency reported, citing Russia’s defence ministry. The report could not be verified.

Italy’s prime minister Giorgia Meloni reiterated her opposition to weapons supplied to Ukraine being used on Russian soil, after Nato chief Jens Stoltenberg told the Economist the restriction should be lifted. “I don’t know why Stoltenberg said such a thing, I think we have to be very careful,” Meloni told Italian television, while adding that “I agree that Nato must remain firm, not give the signal that it is giving in.”