KYIV, Ukraine (AP) — U.S. Secretary of State Antony Blinken has arrived in Kyiv on an unannounced diplomatic mission to reassure Ukraine that it has American support as it struggles to defend against increasingly intense Russian attacks. The two-day visit starting Tuesday comes less than a month after Congress approved a long-delayed foreign assistance package that sets aside $60 billion in aid for Ukraine, much of which will go toward replenishing badly depleted artillery and air defense systems. It’s Blinken’s fourth trip to Kyiv since Russia invaded Ukraine in February 2022. U.S. officials say Blinken will underscore the Biden administration’s commitment to Ukraine’s defense and long-term security.