Paul Amos, who was detained while entering the country in Los Angeles, is alleged to have forged official-looking documents that were used to convince Citibank staff to transfer funds belonging to the Bank of Ethiopia to accounts set up by co-conspirators all over the world.
FBI investigators who drew up the indictment said the alleged plot involved accounts in the US, China, Japan, Australia, South Korea and Cyprus.
Mr Amos has pleaded not guilty to a charge of conspiracy to commit wire fraud. If convicted, he faces up to 30 years in prison.
The attempted fraud is said to have been uncovered when several of the banks that held the alleged conspirators' accounts contacted Citibank to say the transactions could not be properly processed.
According to reports in the US cited by This Day Online, the money has been recovered and returned to the Bank of Ethiopia.