New satellite imagery appears to reveal extensive damage to a strategically significant airbase in central Syria used by Russian forces after a reported attack by so-called Islamic State (IS).
Four helicopters and 20 lorries were destroyed in a series of fires inside the T4 base last week, the images from intelligence company Stratfor suggest.
The cause of the fires is unconfirmed.
The Russian military has denied reports that it had lost helicopters at the base as a result of an IS attack.