Syrian government and opposition forces have traded blame over an alleged chemical attack in the village of Kafr Zita, Hama province on Friday.
"Regime planes bombed Kafr Zita with explosive barrels that produced thick smoke and odours and led to cases of suffocation and poisoning," said Rami Abdel Rahman, who heads the London-based Syrian Observatory for Human Rights.
But Syrian state TV accused the Al Qaeda-linked Nusra Front for the attack, which it claimed left at least two people dead.
"There is information that the terrorist Nusra Front released toxic chlorine... leading to the death of two people and causing more than 100 people to suffer from suffocation."
It went on to claim that the Nusra Fron was preparing other chemical attacks elsewhere in Hama, as well as in the northern province of Idlib. The channel did not say how it knew of the purported plans.
An opposition activist told Al Arabiya that the attack in Hama occurred after regime aircraft bombarded the village, which has seen fierce clashes between government and rebel forces.
The Syrian National Coalition has responded by urging the United Nations to conduct a "quick investigation into the developments related to the use of poisonous gas against civilians in Syria." The opposition group also claimed an additional chemical attack had taken place in the Damascus suburb of Harasta.
This is not the first reported incident of chemical weapons usage since the start of international efforts to destroy Syria's chemical arsenal.
In February opposition groups claimed the government had killed at least a dozen people with chemical weapons in the town of Deraya. Those claims were viewed with relative skepticism, but these most recent reports may be taken more seriously since both sides have confirmed the use of chemical agents.
Last August a chemical weapons attack by government forces near the capital Damascus killed hundreds of people, sparking international outrage. A threatened military intervention by the US was only averted after the Syrian government signed up to a Russian-led proposal to decommission its chemical weapons stockpile.