BEIRUT -- Syrian rebels shot down a military helicopter in the country's east, killing eight government troops on board as President Bashar Assad's troops battled opposition forces inside a sprawling military air base in the north for the second straight day, activists said yesterday.
The downing of the helicopter was a welcome victory for rebels fighting to oust Assad as the two sides remain locked in a stalemate in the more than 2-year-old conflict.
Meanwhile, a Syrian opposition group said yesterday that more than 42 soldiers were killed in reported Israeli airstrikes Sunday outside Damascus, attacks that raised concerns about an escalation of the conflict.
And in Geneva, a UN commission probing alleged war crimes and other abuses in Syria Monday distanced itself from claims by one of its members that Syrian rebels have used the nerve agent sarin, but not the regime.
The panel said it has no conclusive evidence about the alleged use of sarin as a chemical weapon.
In Washington, White House spokesman Jay Carney said it's highly likely that the Assad regime and not the Syrian opposition was behind any chemical weapons use in Syria.
The dueling statements highlighted the difficulties of investigating allegations of chemical weapons use.
President Barack Obama has said the use of chemical weapons by the regime is a "red line," but he needs more time to determine if Assad's forces had used chemical weapons in Syria's civil war.
The latest controversy was sparked by Carla Del Ponte, a former war crimes prosecutor.
She told the Italian-language Swiss public broadcaster SRI in an interview late Sunday that her panel's investigators have "strong, concrete suspicions but not yet incontrovertible proof of the use of sarin gas from the way the victims were treated."
"We have evidence on the use of chemical weapons, in particular sarin. Not by the government, but the opposition," Del Ponte said, adding that this was based on interviews with victims, doctors and field hospitals in neighboring countries.
Yesterday, the commission said that it "wishes to clarify that it has not reached conclusive findings as to the use of chemical weapons in Syria by any parties to the conflict."