The Obama administration says it has "high confidence" that Syria's government carried out a chemical weapons attack last week outside Damascus, the capital _ killing 1,429 people.

The U.S. chemical weapons assessment says Syrian President Bashar Assad's government used an unidentified nerve agent in the attack. The report cites human and satellite intelligence that it says backs up publicly available videos and other evidence.

The unclassified report says at least 426 children died.

The report says the "high confidence" assessment is the strongest position that U.S. intelligence agencies can take short of confirmation.

It dismisses the Assad government's contention that rebels were responsible.

The U.S. says additional intelligence remains classified but is being provided to allies and Congress.