Poland has issued a letter of request to procure 32 F-35A Joint Strike Fighters to replace its aging fleet of Russian-made fighters, the country’s defense minister said May 28.

“Today we sent a request for quotation (LOR) to our American partners regarding the purchase of 32 F35A aircraft along with a logistics and training package,” said Polish Minister of Defence Mariusz Błaszczak in a translated tweet. “It’s time to replace post-Soviet equipment with the most modern fighters!”

Lockheed Martin’s F-35 Lightning II at the 2018 Paris Air Show. Photo: Lockheed Martin

The letter of request marks the first formal step in Warsaw’s pursuit of the fifth-generation fighter, made by Lockheed Martin [LMT]. The U.S. and Polish governments will next work through the process to reach a letter of offer and acceptance before the State Department reviews the potential sale and notifies Congress of an intent to make a foreign military sale.

Lockheed spokesman Mike Friedman said in a Tuesday email to Defense Daily that the company looks forward to working with the U.S. and Polish governments as the process moves forward.

“This is a significant step on the path to enhancing Poland’s armed forces and further strengthening ally partnerships,” he said, noting the F-35’s presence in NATO members’ fleets.

Poland currently flies Soviet-era MiG-29 Fulcrum and Su-22 Fitters in its fighter fleets, as well as 48 Lockheed Martin-made F-16 Block 52 aircraft. Should the country be approved to procure the F-35A, it would become the fifth foreign military sales (FMS) customer for the Joint Strike Fighter following Israel, South Korea, Japan and Belgium.

F-35 Program Executive Officer Vice Adm. Mat Winter told lawmakers last month that the program office had seen interest in the aircraft from countries including Poland, Singapore, Greece, Romania and Spain. Meanwhile, Canada, Finland and Switzerland have also publicly weighed the option of procuring the F-35.

Poland’s announcement comes as Congress grapples with the prospect of cutting F-35 partner nation and NATO member Turkey out of the aircraft partnership so long as Ankara moves forward with plans to procure the Russian-made S-400 surface-to-air missile system. U.S. defense officials have publicly stated that the S-400 system is incompatible with the F-35 and other NATO systems.