WASHINGTON — The German Air Force has sent a written request for classified data from the U.S. military on the F-35 fighter jet, reported Reuters.

Germany, which is preparing to replace its aging fleet of fighter jets, has not authorized a procurement plan, nor has it committed to a specific platform to replace its fourth-generation warplanes. The letter noted that the Defence Ministry would hold "an in-depth evaluation of market available solutions, including the F-35, later this year."

Germany may be aiming to bolster its hand in negotiations with its European partners over the development of the next generation of European warplanes. Despite the potential resistance by labor unions if Germany were to purchase the American-made fighters, military sources say buying the F-35 could make sense for Germany given both steady declines in the cost of the U.S. jet and technical challenges with the Eurofighter aircraft.

Key NATO allies of Germany — Britain, the Netherlands, Norway, Turkey and Italy — are already purchasing the F-35 to replace their own dated fleets, and other European countries are also reportedly considering purchasing the F-35.

"In order to understand (the) F-35's cutting-edge technologies, the German Air Force is requesting a classified brief of the F-35's capabilities in general and especially concerning sensor suites, information management and operational capabilities," the letter read.

Since Germany is not part of the international consortium that developed the F-35, the U.S. government must approve the request for classified data. The F-35 program office in the Pentagon said it received the letter and is "working to support the German Air Force request."