"On behalf of the Syrian people, I express my deepest condolences in connection with the crash of the Russian military aircraft IL-20 in the waters of the Mediterranean Sea," the telegram reads.
He also expressed the hope that the tragedy will not stop the struggle between Russia and Syria with terrorism.
At the same time, Assad called the plane crash the result of Israel's arrogance.
Previously, the Kremlin reported that Putin and Assad did not discuss the incident with the IL-20.
According to the statement of the Ministry of Defense of Russia, the IL-20 was shot down by Syria's air defense because of the fact that the Air Force pilots were covered by a Russian airplane.