It has been reported that a Russian transport plane has crashed in Syria killing all 26 passengers and six crew members believed to have been on board, the defence ministry says.
According to BBC, the An-26 plane crashed during landing at Hmeimim airbase, near the Syrian coastal city of Latakia, the ministry is quoted as saying by Russian media.
The plane was not fired upon, Russia says, and preliminary data suggests a technical malfunction could have caused the crash.
An investigation is now under way.
On 31 December 2017, Russian warplanes were damaged at Hmeimin after a rebel mortar attack.
Hmeimim is Russia's main base for air strikes on rebel groups in Syria - strikes that have enabled Syrian President Bashar al-Assad's forces to recover much lost ground.
Russian air strikes are said to have killed many civilians - though Moscow insists that it only targets rebel "terrorist" fighters.