NEW : the Joint Chiefs wo n't rule out more help for rebels , has n't verified latest claim on chem weapons . Chairman of White House points to lack of trust as major issue in military involvement in U.S. . They feel like they are on their own on this . '' Syrian opposition groups do n't trust the Obama administration , experts on the region say . Distrust stems from the Syria debate over chemical weapons , likely to reignited after latest claims .
NEW : the Joint Chiefs wo n't rule out more help for rebels , has n't verified latest claim on chem weapons . Chairman of White House points to lack of trust as major issue in military involvement in U.S. . Syrian opposition groups do n't trust the Obama administration , experts on the region say . Distrust stems from the Syria debate over chemical weapons , likely to reignited after latest claims .