Last week, the government organised mass protests against the sanctions, demanding that they be lifted.
HARARE - Zimbabwe Foreign Minister Sibusiso Moyo accused the US ambassador of acting like a member of the opposition, insulting the authorities.
Last week, US ambassador Brian Nichols said it was the authorities who were to blame for the country's dire economic straits, not US economic sanctions.
On Friday, the US said that it would refuse entry to Zimbabwe's security minister as it voiced alarm over the government's crackdown on protests and the opposition.
Minister Moyo said in a statement that Nicol's remarks showed a lack of respect for his host country and flouted diplomatic conventions which do not allow an ambassador to interfere in a country's internal affairs.
Nicols comments were "grossly partisan in nature" and no one should think that because Zimbabwe was a welcoming, tolerant country, it was weak and would "simply ignore or tolerate any form of abuse," Moyo said in a statement.
"No diplomat, let alone an ambassador, should allow themselves to behave or to conduct themselves like some kind of opposition member, with complete disregard for all norms of permissable diplomatic protocol," he added.
The US and European Union have imposed sanctions for more than 20 years on Zimbabwe, targeting especially the late president Robert Mugabe and his family who they accused of massive corruption.