The $US89 million ($NZ141 million) would go towards the largest US de-mining programme yet in Ukraine, and the official compared Ukraine's challenge to attempts to disarm unexploded ordnance in Vietnam, Cambodia and Laos following the American war of the 1960s and 70s in Southeast Asia.
"If you look at some conflicts in the not so distant past, the Vietnam War for example, we're still clearing ordnance in Southeast Asia 50 years after that war ended. This may be on par with that," the official said on Tuesday.
The programme would be run through contractors and non-governmental organisations the official said. He said the money, part of which comes from Ukraine-linked budget requests, will not only fund training, but specialised mine detection and earth moving equipment if need be.
A Ukrainian official said the aid addressed one of the country's most important tasks.
"By our estimates, 160,000 square kilometres of Ukrainian land need demining, which is about the size of Virginia, Maryland and Connecticut combined," said Andriy Yermak, President Volodymyr Zelenskiy's top aide.
"This aid will accelerate Ukraine's recovery," Zelenskiy's chief of staff said in a Telegram post.
The United States is the top financial supporter of conventional weapons destruction, according to a State Department report, and has provided more than $US4.2 billion in assistance to over 100 countries from 1993 through 2021.
The US is also the world's largest weapons exporter.
