UN human rights investigators have spoken to the victims of Syria’s civil war and gathered medical testimonies which point to the Syrian rebels having used sarin nerve gas, while any allegations of its use by the government remain unsubstantiated.

The United Nations independent commission of inquiry on Syria has concluded that no evidence of the use of sarin by Syria’s government troops has so far been uncovered, said the lead commission member Carla Del Ponte on Sunday.

In an interview to Swiss-Italian television, Del Ponte revealed that the "investigators have been in neighboring countries interviewing victims, doctors and field hospitals and, according to their report of last week which I have seen, there are strong, concrete suspicions but not yet incontrovertible proof of the use of sarin gas, from the way the victims were treated."

The new report now makes the long-standing accusations of the use of chemical weapons by Syrian President Bashar Assad look weaker: "This was use on the part of the opposition, the rebels, not by the government authorities," Del Ponte continued, though she has given no indication yet of where and when the nerve agent was used.

People are brought into a hospital in the Khan al-Assal region in the northern Aleppo province, as Syria's government accused rebel forces of using chemical weapons for the first time. The opposition denied the claim, saying instead that government forces might have used banned weapons.(AFP Photo / HO-SANA)

However, despite the apparent turn-around, the investigation headed by Carla Del Ponte in Geneva is still separate from the one initiated by UN Secretary-General Ban Ki-moon. The latter has stalled, for the time being.

The Russian Foreign Ministry has urged against the escalation in the region. 

"We insist that this most important issue and escalating of the anti-Syrian emotion not be politicized," the official statement said. "We confirm it's inappropriate to delay - under created and dangerous pretexts - the response to Syria's call onto the UN in connection with the use of chemical weapons by the forces of the opposition in March of this year."

March saw two alleged chemical attacks take place in Aleppo and the capital Damascus, while December of last year saw one in Homs as well, with accusations being thrown back and forth between the government and the opposition.

The US has been insinuating that all such transgressions are by the Syrian government, and has been getting more insistent on using any available pressure point s to weaken Bashar Assad, the latest being a threat by US Defense Secretary Chuck Hagel that the country may be on the verge of openly sending weapons to the Syrian rebels.

There was also talk of a ‘red line’ being crossed if any evidence pointing to the government’s use of chemical agents was discovered. President Barack Obama has warned that this would be a "game-changer" for the Syrian president. He added to this at a recent conference in Mexico, saying "As we've seen evidence of further bloodshed, potential use of chemical weapons inside of Syria, what I've said is that we're going to look at all options."

Yet, the information from the UN probe that alleges that chemical weapons were in fact being used by the rebels has coincided with Israel carrying out two bombings of Syria within a space of 72 hours, with the US preferring to leave the incident without comment.

The United States has previously said it has "varying degrees of confidence" that president Assad has used chemical weapons against his population.

The Syrian uprising, which has been ongoing for two years now, has claimed over 70,000 lives and displaced upwards of 1,2 million people into neighboring countries.

Medics and other masked people attend to a man at a hospital in Khan al-Assal in the northern Aleppo province, as Syria's government accused rebel forces of using chemical weapons for the first time. The opposition denied the claim, saying instead that government forces might have used banned weapons.(AFP Photo / HO-SANA)

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