'Chemical' attack by Assad regime in Syria kills 1300 in 'massacre', the opposition says
The allegations of gassing civilians dwarfed all previous such accounts in the increasingly bloody civil war.
The Syrian Network for Human Rights reported that 647 Syrians were killed in the attacks, and it attributed nearly 590 of those deaths to chemical weapons.
The Syrian Observatory for Human Rights, considered the most authoritative group tracking casualties in the conflict, estimated at least 136 dead from an air assault but didn't address whether chemical weapons appeared to be involved.
Videos distributed by activists, the authenticity of which could not immediately be verified, showed medics attending to suffocating children and hospitals being overwhelmed.