Washington (CNN) -- Singapore Airlines Cargo on Tuesday became the 20th air carrier to be charged in a massive ongoing global investigation into air cargo price-fixing, the Justice Department announced.
The carrier pleaded guilty in federal court in Washington and agreed to pay a criminal fine of $48 million.
Government lawyers said Singapore Airlines Cargo and the other carriers had secretly conspired to set rates for shipments to and from the United States.
The Justice Department Antitrust Division said criminal fines against all of the airlines now total $1.7 billion.
Four air cargo industry executives have been sentenced to serve prison time. Charges are pending against 13 other executives, the Justice Department said.
Prosecutors said the price-fixing conspiracy lasted at least from 2002 to 2006.
Singapore Air Cargo has promised to cooperate with the U.S. government's continuing investigation.