Ukrainian President Volodymyr Zelensky toured a Pennsylvania ammunition plant on Sunday as he began a key visit to the United States in which he is expected to present his blueprint to defeat Russia to President Joe Biden and other allies.

Zelenskyy is gambling that his surprise attack into Russia can convince Putin to negotiate an end to the 2½-year-old war which has produced an estimated one million casualties. But Putin continues to rely on the sheer weight of numbers to grind Ukraine down.

Strikes on weapons arsenals are crucial to weaken Moscow’s overwhelming superiority in battlefield firepower, analysts said.