Iran , North Korea , and Hezbollah `` will look at the United States and say 'Nothing means anything ' -- NEW : Arab League condemns attack , warns Syrian opposition . Kerry says blood and hair samples show ` ` signatures of sarin '' The U.N. says its investigation will be ` ` impartial and credible '' Syrian opposition : Obama has brought false hope to those suffering .
NEW : Arab League condemns attack , warns Syrian opposition . Kerry says blood and hair samples show ` ` signatures of sarin '' The U.N. says its investigation will be ` ` impartial and credible '' Syrian opposition : Obama has brought false hope to those suffering .