Syria's government and rebels accused each other of firing a rocket loaded with chemical agents outside the northern city of Aleppo on Tuesday, March 19 an attack which a cabinet minister said killed 16 people and wounded 86, Reuters said.

President Bashar al-Assad, battling a two-year uprising against his rule, is widely believed to have a chemical arsenal. Syrian officials have neither confirmed nor denied this, but have said that if it existed it would be used to defend against foreign aggression, not against Syrians. There have been no previous reports of chemical weapons in the hands of insurgents.

Information Minister Omran al-Zoabi said rebels fired a rocket with chemical weapons at the town of Khan al-Assal, southwest of Aleppo, in what he called a "dangerous escalation".

But a senior rebel commander, Qassim Saadeddine, denied the accusation and said he believed forces loyal to Assad had fired a Scud missile carrying chemical agents.

U.S. President Barack Obama, who has resisted overt military intervention in Syria's two-year-old civil war, has warned Assad that any use of chemical weapons would be a "red line".

Zoabi said 16 people were killed and 86 wounded - many of them critically - in the attack which he said was launched from Aleppo's southeastern district of Nairab towards Khan al-Assal.

He said Turkey and Qatar, which have supported rebels, bore "legal, moral and political responsibility" for the strike.

Saadeddine, a spokesman for the Higher Military Council in Aleppo, said the rebels had not carried out the attack.

In the capital Damascus, activists released video footage on Tuesday showing men and boys lying in a medical center, all of them receiving oxygen, in the aftermath of what they said was a separate chemical attack.