official who spoke on condition of anonymity, Reuters reports. "The Secretary's mission here is really to talk about how our supplemental assistance is going to be executed in a fashion to help shore up their defenses (and) enable them to increasingly take back the initiative on the battlefield," the official said.The official mentioned that the artillery, along with long-range missiles referred to as ATACMS, and air defense interceptors, which were authorized by President Joe Biden on April 24, were already being delivered to the Ukrainian forces.On May 10, Biden authorized a $400 million defense aid package for Ukraine, according to a statement on the White House's website. The new package included ammunition for Patriot and NASAMS air defenses, Stinger anti-aircraft missiles, HIMARS systems and ammunition, 155 mm and 105 mm artillery shells, and equipment to integrate Western launchers, missiles, and radars with Ukrainian systems.While in Kyiv, Blinken will reassure Ukrainian officials including President Volodymyr Zelensky of enduring U.S.