The US State Department has expelled three Venezuelan diplomats in response to last week's expulsion of three consular officials from Caracas.
Jen Psaki, the department's spokeswoman, said on Tuesday that First Secretary Ignacio Luis Cajal Avalos, First Secretary Victor Manuel Pisani Azpurua, and Second Secretary Marcos Jose Garcia Figueredo, had 48 hours to leave the US.
The Venezuelan president, Nicolas Maduro, expelled three US diplomats from Caracas on February 17, saying they were supporting opposition plots to overthrow him.
Psaki cited US concerns about Venezuela's record on human rights and support for democracy, but said the US remained open to a diplomatic relationship with Maduro.
"Venezuela also needs to show seriousness for us to be able to move forward," she said. "And recent actions, including expelling three of our diplomats, continue to make that difficult."
Elias Jaua, Venezuelan foreign minister, said the US moves were "a retaliation" and "not reciprocity".
Unlike the expelled US diplomats, Venezuelan diplomats were not taking actions against the US or in contact with violent anti-government groups, Jaua said as justification for his country's earlier expulsions.
The two countries have not exchanged ambassadors since 2010, though they have maintained embassies.
Since February 12, Venezuelan opponents of Maduro have been staging countrywide protests that the government says have left at least 15 people dead and wounded about 150.
Authorities have detained 579 people, of whom 45, including nine police officers and members of the National Guard, remain in custody.
Though violent protests have died down, Venezuela remains tense.
Opposition protesters erected barricades to block traffic on major streets in Caracas and elsewhere Monday but there were no major clashes, the AP news agency reported.