U.S. says 1,429 Syrian citizens killed in Aug 21 chemical weapons attack

WASHINGTON (Reuters) - A Syrian chemical weapons attack on August 21 killed 1,429 Syrian civilians, including 426 children, an unclassified U.S. intelligence report concluded on Friday. President Barack Obama is using the report to make the case for retaliation against the Syrian government. The intelligence gathered for the U.S. report included an intercepted communication by a senior official intimately familiar with the attack as well as other human, signals and satellite intelligence, the four-page report said. (Reporting By Steve Holland and Roberta Rampton)