BBC Verify tracked one large Russian Antonov An-124 from Tuesday on plane tracking website Flightradar24. Its publicly available tracker showed it over Russian airspace, travelling in the direction of Syria. It then disappeared from Flightradar24 off the Syrian coast, west of Hmeimim air base, likely because its public tracker was switched off. It can next be seen heading back north six hours later.
David Heathcote, intelligence manager at McKenzie Intelligence, said the rapid collapse of the Assad government meant it was unlikely Russia had a plan to evacuate resources.
He described the activity at Hmeimim air base as “unusual”, suggesting that Russia was storing some resources in the base and preparing to withdraw some equipment and personnel from Syria.
Tayfun Ozberk, a former naval officer and defence analyst, agreed that the imagery indicated “early stages of a Russian withdrawal from Syria, with clear signs of an air-based evacuation.”
“The presence of Il-76 aircraft, the absence of Russian vessels at Tartous, and the organised pre-staging of vehicles and equipment support this conclusion,” Mr Ozberk said.
BBC Verify reported last week how Russian warships had left the port at Tartous, with analysts suggesting they were being stationed in international waters for the time being.
Those vessels have not returned – but more than 100 military vehicles have arrived at the base in recent days, satellite images show.
