Turkey will hold another round of talks with U.S. defense giant Lockheed Martin to resolve their disagreement over the cost of a new multibillion-dollar order for F-16 fighter jets, according to Bloomberg sources.

To facilitate the deal, Turkish President Recep Tayyip Erdogan made a personal appeal to Donald Trump about the F-16 Block 70s during their meeting at the White House in September, the same sources said.

Although Congress approved in February 2024 the acquisition of 40 F-16 Viper fighters from Turkey, Ankara opposes the company’s demand that the buyer cover the cost of upgrading the mission computer and setting up new production lines to address the backlog of orders, according to the sources who spoke on condition of anonymity due to the sensitivity of the issue.

Turkey, the world’s largest F-16 operator after the US, is also seeking access to the mission computer source code so it can incorporate domestically developed missile systems and radars, the same sources said.

It is not clear the total amount of the deal. The price of F-16s varies widely depending on the technical specifications and accompanying package, but typically each aircraft costs tens of millions of dollars.