The presidents of Turkey, Iran and Russia met in Tehran today to discuss the situation in Idlib. This is the province of Syria to which millions of civilians and some fighters have fled as their cities and towns fell to government forces. They were permitted by Russia and Iran-backed fighters to escape to Idlib as part of surrender plans as cities like Aleppo came under government control. Idlib is the last major concentration of a constellation of rebel forces and 2.9 million civilians.

Now, it appears that the province may come under attack.

This meeting in Iran could be the moment in which an attack on Idlib is prepared, held off, or something in between.

The stakes are so high.

Meanwhile, in New York today the Security Council held a meeting on this unfolding situation. The council heard from the UN’s Syria envoy Steffan di Mistura  who reminded the council that Erdogan, Rouhani and Putin are “the guarantors of the last de-escalation zone.”  A top humanitarian official, John Ging told the council that an attack on Idlib “the potential to create a humanitarian emergency on a scale not yet seen by this crisis.”

Two weeks ago, as it became clear that an attack on Idlib could be imminent, I spoke with Jan Egeland, who is a former top UN official and current advisory to the UN’s special envoy for Syria. He described both the geopolitics driving a potential attack on Idlib as well as the profound humanitarian fallout that would result in such a strike. He told me, quite straightforward that it would be a “bloodbath.”