The US has accused Venezuela's government of stealing from a state-run food programme while its own people go hungry.
Marshall Billingslea, a US treasury official, said Venezuelan government officials were over-charging for food.
He said corruption by President Nicolás Maduro and his inner circle had "impoverished millions" of Venezuelans.
The Venezuelan government blames US sanctions for the food shortages the country is experiencing.
Mr Billingslea, who is the Assistant Secretary for Terrorist Financing at the US treasury department, accused President Maduro of "rapacious corruption" and of operating "a kleptocracy".
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He was speaking at an informal meeting of the UN Security Council organised by the US ambassador, Nikki Haley.
"Something is very wrong when citizens of an oil-rich country have to leave in order to beg on Colombian streets to feed their children," Ms Haley said at the meeting.
"That something is the corruption of the Maduro regime," she added.
Despite UN figures which suggest that more than 2.3 million people have left Venezuela since 2014, the Venezuelan government has insisted that the number of people leaving the country is "normal".
Many cite severe shortages of food and medicines as the reasons for leaving.
No Venezuelan representative attended the UN meeting and its mission at the UN did not comment.
But at a separate UN meeting in Geneva, Venezuela's Foreign Minister Jorge Arreaza said that "it has been difficult for Venezuela to import the basics to meet the nutritional and health needs of our people".
Mr Arreaza blamed "unilateral coercive measures" by the US and the European Union for the shortages.
The US has imposed sanctions on the Venezuelan government aimed at - among other things - preventing it from selling off debt. Critics of the sanctions say this makes it hard for Venezuela to tackle its economic problems.
Individual Venezuelan officials, including President Maduro, have also had their assets frozen and some are banned from travelling to the US and the EU.