There was no comment from the government in Damascus or any worldwide agency in the immediate aftermath of the attack.
March 19, 2013: The Syrian government and opposition trade accusations over a gas attack that killed some 26 people, including more than a dozen government soldiers, in the town of Khan al-Assal in northern Syria.
The air strikes also wounded more than 60 people in the town of Khan Sheikhoun in rebel-held Idlib, the Observatory said. The center published footage of medical workers appearing to intubate an unresponsive man stripped down to his underwear and hooking up a little girl foaming at the mouth to a ventilator.
The attack would not be the first time regime forces have been accused of using chemical attacks against their own people.
A gas attack has reportedly taken place in Syria's rebel-held Idlib, killing at least 58 people, with various media outlets reporting that a rocket has since hit a hospital treating the victims.
"If proven, this will be further evidence of the barbarism of the Syrian regime, and the United Kingdom has led global efforts to call to account the Syrian regime and Daesh for the use of chemical weapons and I would urge the Organisation for the Prohibition of Chemical Weapons to investigate this incident as soon as possible".
The Observatory said the attack on a residential part of Khan Sheikhun came in the early hours of Tuesday, when a warplane carried out strikes that released "toxic gas".
Mashrafe to bid adieu to T20 internationals after Lanka series
In Bangladesh , that start time will be 7:30 p.m., while in the United States, the match gets underway at 9:30 a.m. Earlier, Bangladesh managed to post a decent score of 155 for 6 after Mashrafe had won the toss.
The Observatory says numerous victims in the attack on the town of Khan Sheikhoun in the northern province of Idlib were choking, suffocating, vomiting and foaming at the mouth after the bombing. The Syrian government has denied ever using such weapons. The coalition described the attack as a "horrifying massacre".
The town is in Syria's Idlib province, which is largely controlled by an alliance of rebels including former Al-Qaeda affiliate Fateh al-Sham Front.
Claims of chemical weapons attacks, particularly the use of the chlorine agent, are not uncommon in Syria's conflict.
August 21, 2013: Hundreds of people suffocate to death in rebel-held suburbs of the Syrian capital, with many suffering from convulsions, pinpoint pupils, and foaming at the mouth.
The incident occurred a day before a major worldwide meeting scheduled to be held in Brussels on Syria.
In a bid to avert USA military action, the Syrian government officially joined the Chemical Weapons Convention and turned over its chemical arsenal in 2013.
The conflict pits President Bashar al-Assad's government, helped by Russian Federation and Iranian-backed militias, against a wide array of rebel groups, including some that have been supported by Turkey, the United States and Gulf monarchies.