A US grand jury has indicted five men accused of covering up alleged attempts to smuggle $800,000 (£403,000) to Argentina in a suitcase.
Four of the men are in custody in Florida
Argentine President Cristina Fernandez de Kirchner and Venezuela deny claims that the cash was a Venezuelan attempt to boost her election campaign.
The men, four Venezuelans and a Uruguayan, are charged with being undeclared Venezuelan agents in the US.
The money was seized from a businessman at customs in Buenos Aires in August.
Four of the men indicted, Moises Maionica, 36, Rodolfo Wanseele Paciello, 40, Franklin Duran, 40, and Carlos Kauffmann, 35, are in custody in Florida after being arrested last week.
Antonio Jose Canchica, 37, is still at large.
The men could face up to 10 years in prison and $250,000 in fines.
Attorneys for the men have insisted they are innocent.
The indictment came as an Argentine prosecutor told Argentine radio that the businessman from whom the money was confiscated had been seen at the presidential palace two days after the money was seized.
She said a former Argentine government employee had testified that she had noticed Guido Antonini Wilson, a Venezuelan-American, at a function.
He was initially allowed to return to the US after the money was found, but Argentine authorities are now seeking his extradition for questioning.
President Fernandez has described the accusations as a "trashing operation", while Venezuela has rejected them as a "fabricated scandal".
Assistant US Attorney Thomas Mulvihill has said that an FBI recording shows that the money was destined for Ms Fernandez's campaign.
Correspondents say the affair is a political test for Ms Fernandez, who was sworn in as president nearly two weeks ago.
She was elected in October to take over the presidency from her husband Nestor.
US prosecutors say the defendants held meetings in Florida with Mr Antonni Wilson, and attempted to bribe him with $2m (£1m) him to hide the source of the money and its destination.
Mr Antonini Wilson was part of a delegation flown in to Buenos Aires by the Argentine government on a private jet in August.
He is not accused of any crime by the American prosecutors.