A leading Syrian human rights group has given a lower death toll than that claimed by the United States in last month’s apparent chemical attack in Ghouta. The Obama administration says more than 1,400 people were killed, but the widely cited Syrian Observatory for Human Rights says it has confirmed a toll of 502, including 80 children and 137 women. The group’s director, Rami Abdul Rahman, said the United States appears to have based its higher figure on unreliable members of the Syrian opposition.