WASHINGTON, April 27 (Reuters) - A U.S. federal court ordered South African firm Mirror Trading International's boss, Cornelius Steynberg, to pay $3.4 billion for forex fraud, the U.S. Commodity Futures Trading Commission said on Thursday.

The order requires Steynberg to pay $1.7 billion in restitution to defrauded victims and a $1.7 billion civil monetary penalty, which is the highest civil monetary penalty ordered in any CFTC case, the U.S. regulatory agency said in a statement.

The action is also the largest fraudulent scheme involving bitcoin charged in a CFTC case. (Reporting by Kanishka Singh in Washington)