Venezuela has demanded the release of a government-connected businessman who was detained in Cape Verde on US corruption charges, calling his arrest an illegal act of aggression aimed at piling new hardships on the crisis-wracked oil nation.
Alex Saab's arrest on Friday en route to Iran was a major blow to President Nicolas Maduro's government.
US officials believe he holds many secrets about how the socialist leader, his family and top aides allegedly siphoned off millions of dollars in government contracts amid widespread hunger in the oil-rich nation.
It was unclear how American authorities, who had been targeting the Colombian businessman for years, finally caught up with him.
The Justice Department declined to comment as did Saab's American lawyer, Maria Dominguez.
A person familiar with the situation said the 48-year-old Saab was arrested in the Atlantic Ocean archipelago when his San Marino-registered jet made a refuelling stop on a flight to Tehran, where he was believed to be negotiating deals to exchange Venezuelan gold for Iranian gasoline.
Flight tracking data shows the aircraft, which the once globe-trotting Saab had used in the past, departed on Friday from Venezuela's capital, Caracas.
A private jet belonging to Presidential Aviation, a US government contractor formerly owned by the Blackwater private security firm, was ready for a chartered flight from Cape Verde to Miami's private Opa Locka airport on Sunday.
Venezuela's government protested against the arrest, saying that Saab was travelling on a Venezuelan passport and was on a "humanitarian mission" to buy food and medical supplies.
In a statement issued on Saturday night, the government said an Interpol arrest notice for Saab was not issued until a day after his detention, violating international norms and disregarding the diplomatic immunity he enjoys as an "agent of a sovereign government".