MOSCOW, June 2. /TASS/. Russia and Turkey are at an advanced stage of their talks on the delivery of the second regiment set of S-400 ‘Triumf’ anti-aircraft missile systems to Ankara, Head of Russia’s Federal Service for Military and Technical Cooperation Dmitry Shugayev said on Tuesday.

"The dialogue on the delivery of the second regiment set of S-400 systems is at quite an advanced stage and we are waiting for the Turkish side’s final decision," Shugayev said in an interview with the Ekoturk TV Channel.

Russia is ready to discuss with Turkey the possibility of technological cooperation, which implies the participation of Turkish companies in the technological process, he said.

"The negotiations [on this issue] are underway but this is a time-consuming process that takes certain time. But considering the current restrictions over the pandemic, it is quite difficult to predict the time of concluding this contract," he noted.

Russia announced in September 2017 that it had signed a $2.5 billion deal with Turkey on the delivery of S-400 anti-aircraft missile systems to Ankara. Under the contract, Ankara received a regiment set of S-400 air defense missile systems (two battalions). The deal also envisages partial transfer of production technology to the Turkish side.

Turkey is the first NATO member state to purchase such air defense missile systems from Russia. The deliveries of S-400 launchers to Turkey began on July 12, 2019.

Turkey’s decision to acquire the Russian-made S-400 surface-to-air missile systems has caused a sharply negative reaction from the United States and NATO as a whole. The United States is not abandoning its attempts to make Turkey give up the Russian air defense systems.

As Turkey has not yielded to the pressure and has said that it will not give up the S-400 systems, Washington has excluded Ankara from the US program of developing the fifth-generation F-35 fighter-bomber.

The United States is also threatening Turkey with unilateral sanctions over the purchase of S-400 air defense systems but is in no hurry to take these steps out of fear of further worsening relations with a major NATO ally while Ankara warns it will not leave the imposition of these restrictions unanswered.

The S-400 ‘Triumf’ is the most advanced long-range air defense missile system that went into service in Russia in 2007. It is designed to destroy aircraft, cruise and ballistic missiles, including medium-range weapons, and can also be used against ground installations. The S-400 can engage targets at a distance of 400 km and at an altitude of up to 30 km.