Sickened by Wednesday's massacre in al-Qubair, which left at least 78 people dead, UN secretary general Ban Ki-moon has condemned the Syrian regime in the strongest terms yet – describing the events as "shocking and sickening", claiming the Assad regime has "lost its fundamental humanity" and warning “the danger of a full-scale war is imminent and real."

The massacre painfully exposed the difficulties that face the UN monitors when they are simply observing the violence in Syria, let alone trying to stop it. When they were first informed of the killings on Wednesday, they were shot at and blocked from visiting the scene.

With less than 300 monitors in a country the size of England, the Annan plan was never going to work: now, it's clear it has failed. Only increasing the size of the force by a factor of 10 will see any deterrent – and the world now has to think about other, less attractive options, such as safe havens and a peacekeeping force mandated to protect civilians.

Russia and China are holding the world hostage over Syria – even demanding Iran as a mediator for peace. The world urgently needs a Plan B on Syria: Plan A is dead.

Take action: Sign Avaaz's petition to protect Syria's children by sending a 3,000-member UN force to shield civilian populations, and join our call to world powers to stop the merchants of death.