Venezuela said Monday that three U.S. diplomats have 48 hours to leave the South American country, accusing them of conspiring against its government.
The State Department fired back, calling that claim "baseless and false" and saying the United States had not yet received any formal notification of the officials' expulsion.
Venezuelan Foreign Minister Elias Jaua accused the U.S. officials of using a visa program as a cover to meet with youth organizers at private universities "for training, financing and creating youth organizations through which violence is promoted in Venezuela."
The expulsion, which President Nicolas Maduro first announced Sunday, comes after the State Department expressed concerns about rising tensions in Venezuela.
Three anti-government protesters died in clashes last week in Caracas, and authorities have issued an arrest warrant for opposition leader Leopold Lopez on charges including conspiracy and murder in connection with the violence.
The Venezuelan Foreign Ministry sharply criticized the Obama administration.
"The U.S. government is lying when it denounces the arrest of peaceful anti-government protesters," the ministry said in a statement. "The Venezuelan state has acted and will continue acting against violent actions of extreme right-wing groups that are conspiring dangerously against democratic freedoms. ... The world must know that there is enough evidence that the groups that have caused violence in recent days are headed by Mr. Leopoldo Lopez."
Lopez's party, Popular Will, has accused the government of being responsible for violence during the protests.
In a YouTube video posted from an undisclosed location over the weekend, Lopez called for new anti-government protests Tuesday and vowed to show his face in front of Venezuela's Justice Ministry and hand over a list of demands from the Venezuelan people to government officials.
"I made the decision to present myself before the justice system of my country, a corrupt and manipulated system, because I am not a delinquent, I have not committed any crime, and because I have the obligation to deal with this," Lopez said in an exclusive audio statement sent to CNN's Amanpour Monday. "To leave the country or to hide would be to plant doubt about what our motivation is, which is to rally millions of Venezuelans in order to effect change -- social change, political change -- in the face of a reality the affects us all."
Lopez encouraged protesters to be peaceful and to allow him to walk the final stretch to the ministry alone.
"We have raised a flag of change to organize millions of Venezuelans, that we want to effect change in a peaceful manner, not in a violent way," Lopez told CNN.
While opposition groups plan another protest Tuesday, government officials appear to be looking for support beyond the country's borders.
Jaua said he plans to meet Tuesday with ambassadors from Latin American and Caribbean nations, and with ambassadors from Russia and China, to discuss the recent violence.
On Monday, State Department spokeswoman Jen Psaki called for dialogue in Venezuela as tensions mount.
"We support human rights and fundamental freedoms -- including freedom of expression and of peaceful assembly -- in Venezuela as we do in countries around the world," she said. "But as we have long said, Venezuela's political future is for the Venezuelan people to decide. We urge their government to engage all parties in meaningful dialogue."
