Venezuelan President Hugo Chavez has accused the Organization of American States of interfering in Venezuela.
Mr Chavez was responding to comments by OAS Secretary General Jose Miguel Insulza, who criticised a law which gave the Venezuelan president the power to govern by decree.
Mr Insulza said on Friday that the law was "completely contrary" to the Inter-American Democratic Charter.
But Mr Chavez has dismissed the remarks as "shameful".
The left-wing Venezuelan leader accused Mr Insulza of acting on behalf of "US imperialism".
"The poor secretary general of the OAS is a sad spokesman of the empire," Mr Chavez said in his weekly radio address.
But he said the US would not succeed in damaging Venezuela's international prestige.
The enabling law was passed by Venezuela's national assembly last month, shortly before a new parliament took office with an opposition contingent large enough to block major legislation.
It gives Mr Chavez the power to pass laws without needing the support of parliament for 18 months.
Mr Chavez says he needs the powers to deal with the consequences of devastating floods that left more than 140,000 people homeless.
But Mr Insulza said the measure was "not within the spirit or the letter" of the Inter-American Democratic Charter, and said the OAS would probably discuss it.
His comments echo remarks by US Assistant Secretary of State Arturo Valenzuela, who called the law "undemocratic" and said it violated the charter of the OAS.
Venezuelan opposition groups have also condemned the measure, saying it has moved Venezuela closer to dictatorship.
Mr Chavez says he is drawing up a law allowing his government to accelerate the seizure of privately-owned land and buildings to re-house people made homeless by the floods.
He defended the occupation of some private buildings in Caracas last by people claiming to be flood victims.
"They are old and mostly abandoned buildings and when you ask for the owners, it turns out they are in Spain or France or Miami," he said.
The Venezuelan government says it has taken over more then 2m hectares (5m acres) of rural land in recent years, mostly from farms and ranches that were underused or where ownership was not properly established.
It says the aim is to boost food production and give land and livelihoods to the poor.
But opponents of the land seizures have protested, saying they damage the economy and often target working farms.