British defence giant BAE Systems has won a contract with South Korea to upgrade more than 130 F-16 fighter aircraft.
The firm said it was not in a position to confirm the value of the contract, but there have been reports that it could be worth more than a billion US dollars, with the bulk of that going to BAE.
The upgrade of the avionics and electronic systems will take place in the United States over the next decade.
Dave Herr, president of BAE Systems Support Solutions, said: "This is a strategic international win for us, significantly expanding our aircraft upgrade and modification business.
"We have extensive capabilities that span across BAE Systems, and I am confident that our team offers the best value to the customer."
Gordon Eldridge, vice president and general manager of Support Solutions' aerospace solutions business area, said: "This selection further demonstrates that we are a leading provider of integration, avionics and mission computers for F-16s, and we will continue to offer our capability to customers across the globe."