At least 200 civilians have been killed in Russian air strikes in Syria, an Amnesty International report says, quoting witnesses and activists.
The human rights group accused Russia of using cluster munitions and unguided bombs on civilian areas, and said such attacks could constitute war crimes.
Moscow insists it is targeting only the positions of "terrorist" groups.
Amnesty said in its report it is also researching concerns about the US-led coalition air strikes in Syria.
The US has rarely acknowledged civilian deaths in its aerial bombardment of the so-called Islamic State (IS), which began in September 2014.