Turkey could acquire the second part of the S-400 air defense system purchase from Russia, the country’s top defense body head said late Tuesday.

Ismail Demir, chairperson of the Presidency of Defense Industries (SSB), speaking to the public broadcaster TRT, said the purchasing of the second batch of the Russian-made system was on the table from the very beginning.

Turkey’s decision is what it has always been, it didn’t change according to what others have said, he noted.

Ankara's purchasing S-400 air defense systems, of which the first delivery arrived in July 2019, has been a point of long-standing contention between Turkey and the United States.

The U.S.' response to the purchase was to unilaterally expel the NATO ally Turkey from the F-35 fighter jet development program, where it was a major manufacturer and buyer.

In 2002, Turkey joined several other NATO allies who agreed to buy the F-35, and five years later reached a deal to participate in its production, an agreement worth potentially billions of dollars for Turkish industries. Ankara had ordered more than 100 F-35 jets.

Turkey has called the move unjust and demanded reimbursement for its $1.4 billion payment.

Washington argues that the S-400s could be used by Russia to covertly obtain classified details on the F-35 jets and that they are incompatible with NATO systems.

Turkey, however, insists that the S-400 would not be integrated into NATO systems and would not pose a threat to the alliance.

Washington later also sanctioned Turkish defense industry officials, including Demir himself, while U.S. senators have time to time said the country may face more sanctions if continues to purchase the Russian system.

Ankara says it acquired the system after the U.S. refused to sell Patriots in the first place.

Meanwhile, most recently, the U.S. State Department said in a letter to Congress that a potential sale of F-16 fighter jets – produced by the same company that makes F-35s – to Turkey would be in line with U.S. national security interests.

The letter acknowledged the strained relations between the U.S. and Turkey while at the same time describing Turkey's support and defense ties with Ukraine, amid Russia’s war in the country, as "an important deterrent to malign influence in the region."

Demir, meanwhile, also commented on the domestic projects, saying the products developed by Turkish defense industry companies can compete and overthrow their peers. He added that the country is using its domestic weapons and defensive systems during the security operations it conducts.

Most recently, the country’s landmark combat drone Akıncı, developed by drone magnate Baykar, has joined its first major operation ever as Turkey launched a military offensive against PKK terrorist targets in northern Iraq.

The company’s other drone, the Bayraktar TB2, which earned worldwide fame after being tested on combat zones, has been widely used and sold to a range of countries, including Ukraine, Qatar, Azerbaijan and Poland.