Under tight security, Ukrainian President Volodymyr Zelenskyy on Sunday visited a Pennsylvania ammunition factory to thank the workers who are producing one of the most critically needed munitions for his country's fight to fend off Russian ground forces.

Volodymyr Zelenskiy began his visit to the US with a stop at an ammunition plant in Pennsylvania, a critical swing state that will help determine the outcome of November’s US presidential election.

The Ukrainian president's visit aims to rally support for the war-torn country while doubling as a campaign effort to convince Washington for permission to use long-range weapons to strike Russian armed forces.