The Defense Department believes that Turkey's S-400 surface-to-air missile system will soon be ready to track aircraft in the region, a top official said Tuesday.
"We anticipate that being fully operational toward the end of the year," Under Secretary of Defense for Acquisition and Sustainment Ellen Lord told reporters during a briefing at the Pentagon.
Despite months of efforts to sway the NATO ally from purchasing the S-400, Lord said the process to unwind Turkey from the F-35 Joint Strike Fighter program is still on track.
The Pentagon in July officially booted Turkey from participating in the program over its purchase of the Russian-made S-400 system and began phasing out parts the country produces. Turkish industries produce 937 parts for the F-35, including items for the landing gear and fuselage.
"We're on the path to March 2020 to transition all of those parts out [and] ... the U.S. absorbed about a $600 million bill for that," Lord said, reiterating previous comments she's made on how much it will cost the DoD to find new suppliers.
Additionally, Turkish instructors, pilots, maintainers and personnel who had access to the Joint Program Office were required to leave the United States by July 31.
"Unfortunately, Turkey's decision to purchase Russian S-400 air defense systems renders its continued involvement with the F-35 impossible," the White House said in a statement in July. "The F-35 cannot co-exist with a Russian intelligence collection platform that will be used to learn about its advanced capabilities."
That same month, Turkish and Russian officials announced that Turkey had formally taken delivery of its first set of S-400 system equipment, showing multiple videos of it arriving at Murted Air Base, northwest of Ankara. In May, it was reported that Turkish military personnel had begun training on the S-400 in Russia.
Turkey's decision to buy the S-400, known to Moscow as the "F-35 killer," has been in the works for years.
In 2017, Turkey firmed up a verbal agreement with Russia to purchase the S-400. It came after relations between the countries slowly began to ease: Turkish President Recep Tayyip Erdogan in 2016 formally apologized to Russian President Vladimir Putin for the shootdown of a Russian Sukhoi Su-24 strike aircraft in Turkish airspace in 2015.
F-35 deliveries to Turkey had originally been slated to occur between late summer and the end of the year.