Today, the United Nations Security Council will convene in New York to debate the inevitable final assault on the rebel enclave of Idlib in northwest Syria, with the forces of the regime of President Bashar Al Assad assisted by the air power of Russian strike aircraft and Hezbollah militia forces on the ground that are aligned with Iran. Already, air strikes have hit rebel positions in the opening act of the assault. As it stands now, more than half of the three million people living in this enclave have been displaced by fighting that has ripped Syria apart these past seven years.

All the conditions are in place now for what could very well spiral downwards into a humanitarian tragedy of unparalleled proportions and the focus of the Security Council meeting must be to avert that and ensure the safety and security of those civilians trapped in the last remaining rebel redoubt.

United States President Donald Trump has already sternly cautioned the regimes in Damascus, Tehran and the Kremlin not to put civilian lives at risk, warning ominously that any use of chemical weapons, as has occurred in the past, will be met with an appropriate response.

In the weeks leading up to now, there has been relative calm as forces aligned with the regime planned and prepared their assault, and on Wednesday, heavy shelling fell on the enclave — normally a precursor to an assault by ground forces.

The international community has witnessed such assaults on rebel strongholds before, and on each previous occasion it took agonising days and many failed efforts for a ceasefire to be put in place, or for the sick, old, innocent and injured to be removed from those besieged redoubts. The ferocity of the fighting too ensured that these cities were reduced to ashes and broken bricks, with civilians finding little shelter from air strikes, barrel bombs, chemical attacks, shelling and heavy gunfire.

As the Security Council gathers, all who have followed the war in Syria know of the scale of tragedy that is likely to unfold. But who can stop it now?

In Idlib, the enclave is held by a series of rival rebel factions, making the work of finding the conditions for a ceasefire and implementing it even harder in places such as Homs, Aleppo or Eastern Ghouta. Given the massed forces now ranged against the three million cowering in Idlib, the situation indeed seems dire. To avert a horrific tragedy will require brave leaders to make bold choices.