France’s president, Emmanuel Macron; the new German chancellor, Friedrich Merz; the British prime minister, Keir Starmer; and the Polish prime minister, Donald Tusk, started their visit to Kyiv with a solemn tribute to the thousands of Ukrainian soldiers killed in battle, laying flowers at a makeshift memorial at the heart of the capital.

Ukraine and European leaders agreed on Saturday to an unconditional 30-day ceasefire on May 12 with the backing of U.S. President Donald Trump, threatening President Vladimir Putin with new "massive" sanctions if he failed to comply.

The leaders of Britain, France, Germany and Poland headed to Kyiv on Saturday for talks with Ukrainian President Volodymyr Zelenskiy in a show of unity a day after Russia's Vladimir Putin hosted his allies in a Victory Day parade on Red Square.

Russia said on Saturday that fighting had been taking place in four regions of Ukraine despite this week's unilateral ceasefire by Moscow, saying its troops had been forced to respond to Ukrainian attacks.

Ukraine said Friday it had exposed a network of Hungarian spies trying to obtain defense secrets in a border region of Ukraine – the first time it said such an operation has been discovered.

Ukraine's security service says the state-backed spy network sought to obtain information about military defences on its border with Hungary.

Ukraine's SBU security agency said on Friday it had uncovered a spy network run by the Hungarian state to obtain intelligence about its defences, with Hungary responding to what it called "propaganda" by expelling two people at the Ukrainian embassy in Budapest.