US Defense Secretary Lloyd Austin pledged more military aid for Ukraine on Monday during an unannounced visit to Kiev, his fourth since assuming the position in 2021 and at a precarious moment for the country. Austin announced a further $400 million in military aid for Ukraine, which has battled a Russian invasion since February 2022 “I’m back in Ukraine for the fourth time as Secretary of Defense, demonstrating that the United States, alongside the international community, continues to stand by Ukraine,” Austin said on X. The secretary met with Ukrainian President Volodymyr Zelensky and his U…