"As for the possibility for Turkey to purchase an additional batch of the S-400 Triumf anti-aircraft weapon systems, we see no fundamental obstacles to developing the accumulated positive experience in high-tech defense cooperation with the Turkish side," Pilipson said.
The deliveries of Russia's S-400 systems began in July 2019, triggering a crisis in Turkey's relations with the United States.
Washington demanded that Turkey abandon the deal and purchase US Patriot missile systems instead, threatening to delay or even cancel the sales of F-35 fighters to Turkey, or to introduce sanctions.
Ankara rejected the claims and continued negotiations with Russia on an extra batch of the S-400.
