Washington: The US said on Tuesday that it has asked three Venezuelan envoys to leave within 48 hours in retaliation against a similar move by the South American nation last week.

The White House in Washington DC. File pic

State Department spokesperson Jennifer Psaki said her agency had declared First Secretaries Ignacio Luis Cajal Avalos and Victor Manuel Pisani Azpurua and Second Secretary Marcos Jose Garcia Figueredo in the Venezuelan embassy "personae non gratae", Xinhua reported.

They were given 48 hours to leave the US, Psaki told reporters at a regular news briefing.

She said Washington remains open to a diplomatic relationship with Venezuela, as President Nicolas Maduro announced on Monday his plan to nominate a new ambassador to the US.

"Venezuela also needs to show seriousness for us to be able to move forward," Psaki said. "And recent actions, including expelling three of our diplomats, continue to make that difficult."

Caracas accused the American envoys of meeting with university students and instigating protests and unrest in the oil-rich country, where protests since Feb 12 have killed at least 12 people. Psaki had rejected the accusations as "baseless and false".

Washington-Caracas ties have not improved since Maduro took over the presidency from late Hugo Chavez in March 2013, and Maduro had expelled American diplomats twice, sparking US tit-for-tat moves.

The two countries have not had an exchange of ambassadors since July 2010, though Venezuela is flowing 900,000 barrels of oil per day to the US.