U.N. war crimes panel says 14 possible chemical weapons attacks in Syria, and rebel atrocities mounting

Geneva The chairman of a U.N. war crimes panel on Monday said his team was investigating 14 suspected chemical attacks in Syria, dramatically escalating the stakes after diplomatic breakthroughs that saw the Syrian government agree to dismantle its chemical weapons program.

Paulo Sergio Pinheiro said the Geneva-based U.N. panel he heads has not pinpointed the chemical used in the attacks and is awaiting evidence from a separate team of U.N. chemical weapons inspectors expected to be made public later Monday.

That report is expected to add momentum to a deal to eradicate Syria's chemical weapons program.

Pinheiro also said the panel believes Assad's government has been responsible for war crimes and crimes against humanity, while rebel groups have perpetrated war crimes but not crimes against humanity "because there is not a clear chain of command."

While the new assessment from Pinheiro will likely be used by the U.S. and other nations to push for a political solution to the crisis which includes President Bashar Assad handing over power to a transitional government, it also highlights the challenges in finding a viable replacement for him.

The Obama administration has backed an umbrella opposition group based in Turkey, the Syrian National Coalition, but the leaders of that group's military division control only a limited number of the thousands of fighters battling Assad's forces on the ground.

Pinheiro said Monday that had been an "upsurge in crimes and abuses committed by extremist anti-government armed groups along with an influx of rebel foreign fighters," primarily in northern Syria, where the rebels hold more territory.

"Entire brigades are now made up from fighters who have crossed into Syria," he said.

"The point is that these extreme elements have their own agenda and certainly not a democratic agenda that they are seeking to impose," Reuters quoted commission member Vitit Muntarbhorn as saying. "That is a major worry from our side of the fence."

The military and security consultancy IHS Jane's said, meanwhile, that almost half of the fighters battling Assad's military and its allies in Syria were believed to be Islamic extremists.

Secretary of State John Kerry rejected the notion earlier this month that jihadist militants comprise the majority of the anti-Assad fighters in Syria, saying the best estimate of the U.S. government was that 15 - 25 percent were Islamic militants.

Kerry said the claim that Islamists were a majority was "basically incorrect" and argued that the opposition had "increasingly become more defined by its moderation."

Russian leader Vladimir Putin, a long-time ally to Syrian President Assad, appeared the next day to call Kerry a "liar" for his assessment of how many rebels were jihadists.