A United Nations panel investigating war crimes in Syria says it has found no conclusive evidence that either side in the conflict used chemical weapons, distancing itself from a member's claim citing "strong, concrete suspicions" that rebel forces had used sarin gas.
The Independent International Commission of Inquiry on the Syrian Arab Republic said Monday it wanted to clarify "that it has not reached conclusive findings as to the use of chemical weapons in Syria by any parties to the conflict."
White House spokesman Jay Carney said the Obama administration is "highly skeptical" of suggestions that Syrian rebels used chemical weapons. The U.S. State Department added that Washington's position is that any use of chemical weapons in Syria likely would have originated with the government of President Bashar al-Assad.
The statements come after panel member and former war crimes prosecutor Carla Del Ponte told Swiss TV the commission has indications Syrian rebel forces opposed to President Assad used the nerve agent sarin as a weapon.
Del Ponte said her comments were based on testimony from victims, doctors and field hospitals in neighboring countries. She said investigators do not yet have certain proof, and also cautioned that the investigation is not complete. Del Ponte did not provide details about where or when the chemical weapons may have been used.
The commission is separate from a fact-finding mission appointed by U.N. Secretary-General Ban Ki-moon that so far has not been allowed to work inside Syria to probe possible chemical weapons use.
Both the Syrian government and the opposition have accused the other side of using the weapons. British, French and Israeli officials also have charged that Assad's government employed chemical arms against rebels.
Del Ponte said the commission has not yet seen evidence of that use by government forces, but that the investigation continues.
The Obama administration has said U.S. intelligence agencies assess "with varying degrees of confidence that the Syrian regime has used chemical weapons on a small scale in Syria, specifically the chemical agent sarin."
At the same time, the administration said it would "seek to establish credible and corroborated facts" and "fully investigate any and all evidence of chemical weapons use in Syria."
Rebel fighters of the Syrian Kurdish Popular Protection Units (YPG) talk in the Sheikh Maqsoud neighborhood of Aleppo, May 9, 2013.
A view shows damaged buildings and debris in the Khaldiyeh district of Homs, May 9, 2013.
Syrian children play near a water distribution point in the Almyassar central district of Aleppo, May 8, 2013.
A Free Syrian Army fighter holds his weapon in Raqqa province, east Syria, May 6, 2013.
A Free Syrian Army fighter stands behind a pile of sandbags in Raqqa province, east Syria, May 6, 2013.
Free Syrian Army fighters prepare to head toward the front line in the al-Ziyabiya area, Damascus, May 5, 2013.
An armored vehicle is seen parked as Free Syrian Army fighters gather on a street in the refugee camp of Yarmouk, near Damascus, May 5, 2013.
This image taken from video obtained from the Ugarit News shows smoke and fire filling the the skyline after an Israeli airstrike, Damascus, May 5, 2013.
This photo released by the Syrian official news agency SANA shows damaged buildings wrecked by an Israeli airstrike in Damascus, May 5, 2013.
This image provided by ENN shows a protester with a sign reading "If America does not know who used the chemical weapons, so it could be flying saucers from another planet," Sarmada, Idlib, Syria, May 3, 2013.
A man reacts after his grandson was injured during what activists said was shelling by forces loyal to Syrian President Bashar al-Assad, Raqqa province, Syria, May 2, 2013.
Residents inspect a damaged building that was shelled by forces activists say were loyal to Syrian President Bashar al-Assad, Raqqa province, Syria, May 2, 2013.
This photo released by the Syrian official news agency SANA shows Syrian President Bashar al-Assad visiting the Umayyad Electrical Station, Damascus, Syria, May 1, 2013.