Sputnik- Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan discussed the situation in Syria in a phone convsersation with the participation of Kazakh President Nursultan Nazarbayev, the Kremlin press service said Sunday.

MOSCOW (Sputnik) — Erdogan has also extended his heartfelt condolences to Putin over the crash of the Russian Defense Ministry's Tu-154 aircraft in the Black Sea. "A thorough exchange of opinions on the situation in Syria took place [between Putin and Erdogan]. President of Kazakhstan, Nursultan Nazarbayev, who is on a working visit to Russia, took part in the discussion," the press service said in a statement.

Tu-154 aircraft with 92 people on board, including the world-renowned choir of the country's Armed Forces, the Alexandrov Ensemble, and nine journalists, crashed on its way to the Russian airbase in Syria's Latakia province.

Earlier on Sunday, Putin and Nazarbayev visited the laboratories of Biocad, a biotechnology firm in the Leningrad Region, as well as got acquainted with the production technology and product samples at the Diakont plant in St. Petersburg.