Türkiye on Thursday confirmed that a contract for the procurement of F-16 fighter jets from the United States had been signed and said the sides were continuing talks on details.
The Defense Ministry's statement came days after the U.S. State Department said Türkiye had signed a letter of offer and acceptance to purchase the Lockheed Martin-made warplanes.
That brings the two NATO allies closer to completing the prolonged process that sometimes fueled tensions and tested Washington's ties with Ankara.
"The contract has been signed, and delegations from both sides are negotiating the details," the Defense Ministry sources said Thursday.
"The details will be shared with the public later after the decisions to be made on them have been taken."
Türkiye submitted the request to acquire 40 new F-16 aircraft and 79 modernization kits in October 2021 to upgrade the jets in its existing fleet.
This January, the Biden administration formally informed Congress of its intention to proceed with the sale, estimated at around $23 billion, shortly after Ankara formally ratified Sweden's membership in NATO.
The State Department last week hailed "a major step forward" in Türkiye's purchase of the new jets, calling them "the most advanced F-16 ever made available only to closest Allies and partners."
"Just the latest example of U.S. enduring commitment to security partnership with Türkiye," it said in a social media post.
Also lauding the progress, Jeffrey Flake, the U.S. ambassador to Ankara, said the deal was "good for U.S. national security, Turkish national security, and NATO interoperability."
The sale shows growing trust between the sides, Flake said.
Türkiye first sought to purchase Lockheed Martin's more advanced F-35 fighter jets, but the U.S. removed it from the multinational program to buy and help develop and build the warplane in 2019 after it acquired S-400s from Russia.
Washington argued that the air missile defense systems posed a risk to the advanced fighter jet, whereas Ankara insisted they would not be integrated into NATO systems.
Türkiye had ordered about 100 F-35s, and its companies were building some 900 parts of the fighter jet.
Türkiye's request aims to replace the Air Forces Command's aging F-16 fleet in the inventory, which will be phased out starting in the 2030s.
The country is one of the largest operators of F-16 jets, with its fleet comprising more than 200 older Block 30/40/50 models.
Keen to upgrade its air force, Türkiye is also developing its own fifth-generation national combat aircraft, named Kaan, which performed its maiden flight this February.
President Recep Tayyip Erdoğan will join the NATO leaders' summit in Washington next month.
He had been set for talks with his U.S. counterpart, Joe Biden, last month, but what would have been their first White House meeting was postponed due to scheduling problems.
The NATO meeting next month presents an opportunity for an Erdoğan-Biden meeting, given "there's some desire on both sides," Flake, set to leave his post this autumn, said on Wednesday.