US Secretary of State Antony Blinken arrived in Kyiv on Tuesday in an unannounced diplomatic mission to reassure Ukraine that it has American support as it struggles to defend against increasingly intense Russian attacks.

“We know this is a challenging time,” Blinken said in the Ukrainian capital where he met with President Volodymyr Zelenskyy. The visit comes less than a month after Congress approved a long-delayed foreign assistance package that sets aside US$60 billion in aid for Ukraine, much of which will go toward replenishing badly depleted artillery and air defence systems.