British Prime Minister Rishi Sunak announced Friday a new multibillion-dollar aid package for Ukraine during a surprise visit to Kyiv, where he vowed British support for a decade.The pledge came at a crucial time for Ukraine as its allies in Brussels and Washington struggle to secure funding while Russia bolsters its weapon stockpiles and the ranks of its armed forces.Ukrainian President Volodymyr Zelensky hailed the “unprecedented” 10-year security cooperation agreement as well as the £2.5 billion ($3.2 billion) in new military aid earmarked for 2024.