The U.S. made an official offer yesterday to Turkey for a $3.5 billion sale of Patriot air and missile defense systems, which has long been on the negotiating table for the two NATO allies.

Anadolu Agency (AA) reported that the U.S. delegation that arrived in Turkey yesterday made the offer during the meeting with officials from the Foreign Ministry and Defense Ministry. However, no further details were revealed about the offer.

The system includes 80 Patriot missiles and 60 other missiles along with radar sets, engagement control stations and launching stations.

The offer came after the U.S. State Department on Dec. 19 approved a possible sale of the Patriot air and missile defense system and notified Congress of the proposal, saying that Turkey continues to be an essential element of the national security and defense strategy. The State Department also informed Congress about the sale proposal. The move was regarded as a breakthrough after Washington's delayed delivery of F-35 airplanes to Turkey due to Ankara's purchase of Russian-made S-400 defense systems.

Ankara is, on the other hand, opposing any prerequisite in the contract that foresees the cancellation of the S-400 defense systems. President Recep Tayyip Erdoğan also previously said the S-400 missile system negotiations between Ankara and Moscow are a done deal, and the U.S. was not in a position to say something about it, adding that Turkey needs both the Russian S-400 air defense systems and the U.S. F-35 fighter jets.

Turkey had been trying to purchase the air defense system from the U.S. for some time but was never able to get a commitment from Washington when it was needed most. As the U.S. failed to meet the defense needs of Turkey and risked losing its NATO ally, Turkey turned to Russia and decided to purchase Russia's S-400 missile system in 2017, which caused a major political impasse between the two countries.

In the face of Ankara's decision, Washington complained that the Russian system is not compatible with weapons of the NATO air-and-missile defense system and that purchasing the S-400 system would jeopardize Turkey's purchase of F-35 fighter jets, possibly resulting in unavoidable negative consequences for U.S.-Turkey relations. Subsequently, U.S. President Donald Trump approved a defense budget law delaying delivery of the F-35 Joint Strike Fighter jets to Turkey, citing Turkey's purchase from the Russians. Subsequently, the U.S. Congress passed a bill blocking the delivery of the jets until the Pentagon issued a report on Turkish-American relations.