NEW YORK (Reuters) - Two nephews of Venezuela’s first lady facing U.S. charges that they conspired to import cocaine into the United States are getting their defense costs paid for by an unnamed third party, prosecutors said.

In a letter filed on Friday in Manhattan federal court, prosecutors asked a U.S. judge to pose questions to Franqui Francisco Flores de Freitas and Efrain Antonio Campo Flores about their legal fees at a hearing this Thursday.

Both men are nephews of Venezuelan President Nicolas Maduro’s wife, Cilia Flores, and in the last two months brought on large, prominent U.S. law firms to defend them against charges stemming from their arrests in November.

Prosecutors asked U.S. District Judge Paul Crotty to inquire whether a potential conflict of interest exists due to a third party paying their fees and ask Campo Flores and Flores de Freitas if they waive it.

A conflict could mean it was “conceivable that the third party could persuade counsel to avoid seeking leniency by having their client attempt to cooperate, or to advise their client to refrain from testifying in his own defense,” prosecutors said.

Prosecutors also asked the judge to ask who is paying their lawyers, who believe such a question is unnecessary, the letter said.

John Zach, a lawyer for Campo Flores at Boies, Schiller & Flexner LLP, declined comment. David Rody, a lawyer for Flores de Freitas at Sidley Austin LLP, also declined comment.

The case is the latest in a series of enforcement actions and investigations by U.S. authorities that have linked individuals connected to the Venezuelan government to drug trafficking.

The nephews’ case marked an embarrassment to Maduro when it was unveiled last year. Flores in January called the arrest of her nephews a “kidnapping.”

According to a U.S. law enforcement source, the two nephews met a U.S. Drug Enforcement Administration informant in Honduras in October and asked for help sending 800 kilograms of cocaine to the United States through an airport on the Honduran island of Roatan.

According to the indictment, the pair also participated that month in meetings in Venezuela regarding a shipment of cocaine that was to be sent to the United States via Honduras.

Both men have pleaded not guilty.