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. The summit will discuss a U.S. and European proposal for a 30-day ceasefire in the Russian war in Ukraine that if refused by Moscow would see them jointly impose new sanctions, a French diplomatic source said, adding that the step had not yet been finalised. The visit by British Prime Minister Keir Starmer, French President Emmanuel Macron, German...