The United States has seized the cargo on four tankers allegedly loaded with Iranian gasoline destined for Venezuela, the Wall Street Journal reported.
The US Justice Department issued a warrant last month to seize the cargo of the tankers Bella, Bering, Pandi and Luna, tying the shipments to Iran's Revolutionary Guards, which Washington has labelled a terror group.
The four ships were seized at sea and were now en route to Houston, Texas, the Journal reported Thursday, citing US officials.
Iran's ambassador to Venezuela said reports that Iranian tankers had been seized were "yet another lie and psychological warfare" by the United States.
"The ships are not Iranian, and neither the owner nor its flag has anything to do with Iran," Hojat Soltani said on Twitter in Spanish.
Venezuela is almost entirely dependent on its oil revenues but its production has fallen to roughly a quarter of its 2008 level and its economy has been devastated by six years of recession.
Washington's sanctions against President Nicolas Maduro's regime have forced Venezuela, which used to refine enough oil for its own needs, to turn to allies such as US nemesis Iran to alleviate a desperate gasoline shortage.
Iran sent several tankers of gasoline to Venezuela earlier this year to help ease shortages. AFP