With Russian and Syrian government forces poised to begin an all-out military offensive in Idlib, there is a real risk of humanitarian disaster in the last stronghold of the Syrian opposition. The signs are ominous: Russia, the closest ally of Syrian president Bashar al-Assad, resumed air strikes across the province this week after a 22-day pause.
That follows weeks of aerial bombardment and shelling by pro-Assad forces in what seems clearly a prelude to a full-scale assault. The UN special envoy for Syria, Staffan de Mistura, has said panic is spreading among the three million people still living in Idlib.
In a tweet on Monday, US president Donald Trump warned Syria and its Iranian and Russian allies that a "reckless" assault on the north-western province would be a "grave humanitarian mistake". He seems to have little leverage over any of those key players, however.
Turkish president Recep Tayyip Erdogan has also sounded the alarm, saying a large-scale attack on Idlib would be "a serious massacre". But Washington sounds increasingly resigned to the offensive taking place and appears to be focusing now on how, not if, the battle should proceed. Trump's UN ambassador, Nikki Haley, has urged Syria and Russia not to use chemical weapons.
For his part, de Mistura has said he believes both sides in the conflict might have access to chlorine-based weapons, describing them as in the grey zone between conventional and chemical weapons.
Idlib is one of the so-called de-escalation zones set up as a result of talks by Russia, Turkey and Iran last year, as Damascus retook control of large swathes of the country. Erdogan will meet his Iranian and Russian counterparts in Tehran on Friday for a summit that is expected to focus on Idlib. The UN security council is due to meet on the same day. It's vital that a catastrophe be averted. Unfortunately, the best hope of a resolution lies with Russia. Which is to say, there does not seem to be much hope at all.