Syria responsible for chemical warfare: Human Rights Watch

The Human Rights Watch claim they have clear evidence that the Syrian government used chemical weapons, particularly barrels of chlorine bombs, to attack three Syrian cities last month.

The barrels filled with explosives, scrap metal and chlorine gas were rolled out of helicopters. Upon impact with the ground, a 'yellow smoke' could be seen at the base of the dust cloud that followed the explosion, as witnesses reported.

The yellow smoke reports would be consistent with the release of chlorine gas from the blast of industrial compressed gas cylinders.

The reason why the Syrian government is blamed for this attack is that it was the only party in the conflict to make use of helicopters or other aircraft.

Doctors reported that as many as 11 people died as a result of the chemical attack while approximately 500 others presented symptoms linked to chlorine exposure.

After hundreds of civilians died because of a sarin gas attack in Damascus, last year, Syria agreed with the US and Russia to dispose of its chemical arsenal. This last attack could represent a breech of that agreement as chlorine was not declared in Syria's chemical list.