Following up on al-Qaeda’s Nusra Front disavowing the Astana deal on creating de-escalation zones, Russian officials are reporting a massive battle on the outskirts of Syria’s Idlib Province. They are reporting Nusra launched an attempted offensive against Syrian military targets.

This involved, per Russia’s report, Nusra fighters trying to capture a Russian military police unit responsible for monitoring the Idlib ceasefire, and several hours of major battles. At the end of 24 hours, Russia estimated 850 Nusra fighters were killed.

Which is a massively large figure for a single 24-hour period within a single province in Syria. If true, this would likely amount to the elimination of a substantial chunk of the Nusra Front’s fighting force, though of course there are not solid numbers on the size of them, like most rebel forces.

Russia reported three of its special forces wounded in the course of the operation, but no fatalities. They provided no indication what casualties the Syrian military sustained, though given the sheer scale of what happened it would be unlikely Syria didn’t sustain some casualties.