In the message to his Vietnamese counterpart, Ebrahim Raisi wrote: "Vietnam's successes in the national and international arenas in recent decades have been due to the unity and solidarity of the great nation of Vietnam and leaders like you to achieve growth and development."

Six decades ago, the US started spraying toxic herbicide across Vietnam, killing and disabling millions of people. RT speaks to a man who has dedicated his career to repairing the horrific legacy left behind by his country.