Turkey has announced that it is putting the planned purchase of 100 F-35 fighter jets from the US on hold because the Pentagon refuses to share the source code used in the software designed for the aircraft as well as the codes that might be used externally to activate the planes. Defense Minister Vecdi GÃ¶nÃ¼l said on Tuesday, following a meeting of the Defense Industry Implementation Committee (SSÄ°K), that the negotiations over the F-35 procurement tender had not yielded â€œsatisfactory results.â€ He said, â€œWe will evaluate the order in the next meeting, in light of the progress made in the talks by then.â€ He said much ground had been covered in the talks in terms of technology sharing, but this was not enough for Turkey to accept the jets. He said the costs of the project had also increased but that the Turkish side had failed to secure the source code and the remote flight codes for the planes for which it will be paying $16 billion. Without the source code, Turkish engineers wouldn't be able to make any changes to the software that operates the jets. The external flight codes are equally important, if not more, as they can be used externally to navigate the jets. Prime Minister Recep Tayyip ErdoÄŸan, Chief of General Staff Gen. IÅŸÄ±k KoÅŸaner and Minister GÃ¶nÃ¼l attended Monday's SSÄ°K meeting, which took place at the Undersecretariat for the Defense Industry (SSM) offices.