Turkey and the US have signed a contract for the delivery of new American F-16 fighter jets, the negotiations over which were difficult, informed the Ministry of National Defense of Turkey. "The supply contract has been signed. The delegations will continue to discuss the details during the negotiations," a ministry source said, TRT Haber television reported. The exact number of these fighters has not been specified yet. The Turkish mass media reported earlier that Turkey asked the US for 40 new F-16 Block 70 fighter jets and upgrade kits for its existing 79 aircrafts. But the delivery of new F-16 fighters may be delayed until 2028 due to a large number of orders, according to Hurriyet daily.