Russian air strikes in Syria have killed more civilians than they have Isil militants, despite Moscow's claims that its military intervention is intended to defeat the group.
Michael Fallon, Britain's Defence Secretary, said he "deplored" Moscow's use of unguided munitions on civilians and groups fighting the Syrian regime.
The Syrian Observatory for Human Rights said more than 1000 civilians had been killed during Russia's four-month bombing campaign. By comparison, the strikes had killed 893 Islamic State of Iraq and the Levant (Isil) fighters, and 1141 militants from other factions, the monitoring group said.
One of President Bashar al-Assad's staunchest allies, Russia began air strikes on the Government's behalf at the end of September.
Territorial gains have been limited but experts say Moscow has achieved its primary aim of shoring up the regime's northwest heartland in the face of rebel advances.