Syrian state television and rebel forces have traded accusations over a poison gas attack that reportedly caused "suffocation and poisoning" of residents.
Details of the attack on Friday in Kafr Zita, a village in Hama province about 200km from Damascus, remain sketchy.
The Syrian National Coalition, the Western-backed opposition group, said the poison gas attack hurt dozens of people.
Rami Abdel Rahman, director of the UK-based Syrian Observatory for Human Rights which gathers data on the conflict from activists inside Syria, said: "Regime planes bombed Kafr Zita with explosive barrels that produced thick smoke and odours and led to cases of suffocation and poisoning."
But state television claimed that the al-Qaeda-linked Al-Nusra Front had released chlorine gas in the deadly attack on the town.
"There is information that the terrorist Al-Nusra Front released toxic chorine … leading to the death of two people and causing more than 100 people to suffer from suffocation," it said.
"There is information that Al-Nusra Front is preparing to hit Wadi Deif in Idlib province and Morek in Hama province with toxic chorine or sarin," the state broadcaster added.
There was no independent verification of either of the claims. The latest reported poison gas attack comes after a chemical weapons attack outside Damascus last year.
The opposition and much of the international community blamed that attack, which reportedly killed as many as 1,400 people, on the Syrian regime.
The regime denied responsibility, in turn blaming the rebels, but agreed under threat of US military action to turn over its chemical weapons stockpile for destruction.