ANKARA 

The acquisition of air defense systems is Turkey’s right as a sovereign country, a senior main opposition lawmaker said on Tuesday.

"The purchase of S-400s is Turkey's sovereign right,” Unal Cevikoz, Istanbul lawmaker from the Republican People's Party (CHP), said on Twitter, adding that for this reason, US sanctions on Turkey for the purchase are “never acceptable.”

Turkey's steps, as a NATO ally, to strengthen the country's defense should be considered a measure to strengthen the alliance’s defense, Cevikoz said.

Turkey has been a member of NATO for nearly 70 years.

"Turkey was forced to buy the S-400 system, and used its preference in this direction," Cevikoz said, referring to the US repeatedly refusing to sell it US Patriot missiles.

He also urged the government to activate the $2.5 billion defense system "as soon as possible," a step reportedly delayed by the COVID-19 pandemic.

The US on Monday imposed sanctions on Turkey over its purchase of the Russian S-400s.

In April 2017, when its protracted efforts to buy an air defense system from the US proved fruitless, Turkey signed a contract with Russia to acquire the S-400 shield.

US officials have voiced opposition to their deployment, claiming they would be incompatible with NATO systems and would expose F-35 jets to possible Russian subterfuge.

Turkey, however, stressed that the S-400 would not be integrated into NATO systems, and posed no threat to the alliance or its armaments.

Turkey has also repeatedly proposed a working group to examine the technical compatibility issue.