The US Treasury has frozen the assets of two senior Venezuelan officials it accuses of aiding Colombian rebels, in an escalating diplomatic row, reported BBC.
The US said Hugo Armando Carvajal Barrios and Henry de Jesus Rangel Silva were "materially assisting the [Farc rebels'] narcotics trafficking".
The move came as the US revealed plans to throw out Venezuela's envoy, after Caracas expelled the US ambassador.
The US and Bolivia have also engaged in tit-for-tat diplomatic expulsions.
Relations between Washington and Caracas are not thought to have been helped by this week's arrival in Venezuela of two Russian bomber planes taking part in a military exercise.
The US Treasury also imposed sanctions on a third ex-official, former Venezuelan justice minister Ramon Rodriguez Chacin. Analysts say the trio are members of Venezuelan President Hugo Chavez's inner circle.
All three had "armed, abetted and funded the Farc, even as it terrorized and kidnapped innocents," according to a statement from the Treasury's Office of Foreign Assets Control.
Mr Carvajal Barrios is a Venezuelan military intelligence director who has protected Farc drug shipments from seizure, according to the Treasury.
Mr Rangel Silva is another intelligence chief who had pushed for greater co-operation between Venezuela and the Farc, the US Treasury alleged.
And Mr Rodriguez Chacin is Caracas' "main weapons contact for the Farc," the statement charged.
The latest row began when Bolivia threw out the US ambassador in La Paz, Philip Goldberg, accusing him of meddling in the country's internal affairs.
President Evo Morales said the American envoy had been openly siding with an increasingly violent opposition movement in the east of the country.
US officials said the allegations were baseless, but nonetheless expelled the Bolivian ambassador to Washington in retaliation.
This prompted the Venezuelan leader, a Bolivian ally, to step in to the fray.
On Thursday, President Hugo Chavez gave US ambassador Patrick Duddy 72 hours to leave Caracas, telling him: "Go to hell 100 times."
US state department spokesman Sean McCormack told reporters on Friday: "This reflects the weakness and desperation of these leaders."
BBC South America correspondent Daniel Schweimler says the spat between oil-exporting Venezuela and the US is in neither side's interest.
The US is a leading trade partner and a major aid donor to Latin America, so few in the region will be happy relations have plummeted to this new low, says our correspondent.