A Russian cargo plane departed from Russia's air base in the Syrian port city of Latakia for Libya on Saturday, a Syrian security official stationed outside the facility said, following rebels' overthrow of President Bashar al-Assad last weekend.
The official told Reuters that additional Russian departures from the Hmeimim air base in Syria's coastal Latakia province were expected in the coming days.
Increased activity has been observed at the air base throughout the day. In addition to the departing cargo plane, an Ilyushin II-76 cargo plane and an Alligator helicopter were seen landing at the base.
Helicopters were also seen flying within the base, and a SU-34 jet landed for refueling. A Zeppelin hovered overhead, and two trucks carrying Russian flags were seen traveling within the base.
On Friday, satellite images showed Russia moving military equipment at Hmeimim air base, with two Antonov AN-124 cargo planes visible.
Russia, a longstanding ally of Assad, granted the ousted Syrian leader asylum last weekend after helping him to flee his country as the rebels approached Damascus.
Moscow has said it hopes to maintain its two bases in Syria - the Hmeimim air base at Latakia and a naval base in Tartous - in order to keep up efforts against what it called international terrorism.
Russian Deputy Foreign Minister Mikhail Bogdanov said on Thursday contacts with the political committee of Syria's Islamist rebel group Hayat Tahrir al-Sham were "proceeding in constructive fashion".