Throughout the two-year conflict in Syria, the regime of Bashar Al Assad has deployed all types of weapons against the Syrian people, from bullets to mortars, tanks, warplanes and high explosives. The question now is whether the regime has added chemical weapons to its arsenal of terror.
Several reports, citing western intelligence and forensic experts, suggest chemical weapons have indeed been used in at least one area in Syria. Citing British sources, The Times newspaper reported at the weekend that soil samples tested in the UK prove chemical weapons have been used; it makes no inferences about who is responsible. Western diplomats, meanwhile, claim they have "hard evidence" regime forces have used chemical weapons. Consensus is growing that a so-called red line has been breached. So what can the world do about it?
Facts on the ground are still murky. Mr Al Assad has cast blame on the rebels for chemical usage. But ruling out Mr Al Assad's use of these horrific munitions, while yet unproven, would be unwise given his history of violence. Moreover, such a decision - in the past or the future - would be less a strategic choice than a scare tactic to terrorise people in advance of the inevitable battle in Damascus.
Rebel forces have in turn accused the regime of using chemical weapons not only in Khan Al Asal but also in Otaiba, near Damascus. This week, a video emerged showing several patients in Sheikh Maqsoud, a predominately Kurdish area in Aleppo, suffering from vomiting and seizures.
About the only certainty is that evidence that chemical weapons have been used is growing. For the international community, and Syrians alike, this would mark a tragic and regrettable milestone - a point US president Barack Obama once dubbed a red line that would lead to Mr Al Assad being "held accountable".
The use of chemical weapons - the mere suggestion of it, evidence for it, or threat to do so - demands a serious push by world powers. The UN is ready to investigate, but has been stalled by Mr Al Assad. Even without formal verification, Washington must act now. Mr Obama has inched ever closer to providing military support to moderate rebel factions, but chemical weapons revelations suggest this support must be accelerated. It is also time for Russia to end its steadfast support for a ruthless regime.
The war in Syria appears to have entered a new phase. Rhetoric and condemnation are now no longer sufficient courses of action.