The United States has imposed visa restrictions on unnamed Venezuelan officials it accuses of human rights violations and corruption.
Venezuelan President Nicolas Maduro said the measures were an attempt to violate Venezuelan sovereignty.
They build on sanctions imposed last year on officials alleged to have violated the rights of protesters.
The list of officials banned from entering the US has been extended, and now includes family members.
“We are sending a clear message that human rights abusers, those who profit from public corruption, and their families are not welcome in the United States,” said US state department spokeswoman Jen Psaki.
Mr Maduro reacted angrily and said he would write a letter to US President Barack Obama.
“We can’t let an empire that has been eyeing all of us pretend or think it has the right to sanction the country of [Simon] Bolivar,” Mr Maduro said, making reference to the Venezuela-born hero of Latin American liberation.
The sanctions imposed in December were aimed at officials accused over their role in suppressing anti-government protests that shook Venezuela in the first six months of 2014.
‘Look me in the eyes’
The new visa restrictions were announced a day after Mr Maduro accused US Vice-President Joe Biden of plotting a coup against his Socialist government during an energy summit of Caribbean leaders in Washington.
Mr Biden’s office called the allegation “baseless and patently false”.
“President Maduro’s accusations are clearly part of an effort to distract from the concerning situation in Venezuela, which includes repeated violations of freedom of speech, assembly, and due process,” read a statement.
Mr Biden and Mr Maduro had shaken hands in Brazil during Brazilian President Dilma Rousseff’s inauguration ceremony on 1 January.
“Vice-President Biden: Look me in the eyes. I saw you in Brazil, I gave you my hand,” said Mr Maduro in a televised address on Sunday night.
“You, who said this is a new era for relations in Latin America, were going to conspire against Venezuela,” he added.
Relations between the US and Venezuela have been tense for many years. They last had ambassadors in each other’s capitals in 2010.