The U.S. is sending $350 million worth of additional arms to Ukraine as it fights off an invasion by Russian forces, as Defense One reported.

Secretary of State Anthony Blinken announced the “immediate military assistance” after Ukrainian President Volodymyr Zelenskyy turned down an offer to help him evacuate Kyiv as Russian troops continue making slow progress toward the capital.

“I need ammunition, not a ride,” Zelenskyy is reported to have said.

The U.S. package will include ammunition, armor and javelins, a senior defense official told reporters, according to Defense One.

The official also said there is evidence suggesting Russia is “frustrated” with the level of resistance it is meeting in Ukraine. Over the weekend, Russian President Vladimir Putin put his nuclear forces on alert, as the Washington Post noted.

AFP photo by Dimitar Dilkoff via Getty Images