At least 70 people have been killed in a suspected chemical attack on a rebel-held town in northern Syria.
At least 70 people have been killed in a suspected chemical attack on the rebel-held town of Khan Sheikhoun in north-western Syria.
Hundreds suffered symptoms consistent with reaction to a nerve agent after what the opposition and Western powers said was a Syrian government air strike on the area on Tuesday morning.
The Syrian military denied using any chemical agents, while its ally Russia said an air strike hit a rebel depot full of chemical munitions.
Activists and witnesses say warplanes attacked Khan Sheikhoun, about 50km (30 miles) south of the city of Idlib, early on Tuesday, when many people were asleep.
Mariam Abu Khalil, a 14-year-old resident who was awake, told the New York Times that she had seen an aircraft drop a bomb on a one-storey building.
The explosion sent a yellow mushroom cloud into the air that stung her eyes. «It was like a winter fog,» she said. She sheltered in her home, but recalled that when people started arriving to help the wounded, «they inhaled the gas and died».
Hussein Kayal, a photographer for the pro-opposition Edlib Media Center (EMC), told the Associated Press that he was awoken by the sound of an explosion at about 06:30 (03:30 GMT). When he reached the scene, there was no smell, he said. He found people lying on the floor, unable to move and with constricted pupils.
Mohammed Rasoul, the head of a charity ambulance service in Idlib, told the BBC that he heard about the attack at about 06:45 and that when his medics arrived 20 minutes later they found people, many of them children, choking in the street.
The Union of Medical Care and Relief Organisations (UOSSM), which funds hospitals in rebel-held Syria, said three of its staff in Khan Sheikhoun were affected while treating patients in the streets and had to be rushed to intensive care.
Victims experienced symptoms including redness of the eyes, foaming from the mouth, constricted pupils, blue facial skin and lips, severe shortness of breath and asphyxiation, it added.
A Medecins Sans Frontieres (MSF) medical team supporting the Bab al-Hawa hospital, near the Turkish border, confirmed similar symptoms in eight patients brought there from Khan Sheikhoun.
Rescue workers and opposition activists posted photos and videos on social media that showed victims exhibiting the symptoms described by doctors, as well as many people who had died.
The EMC posted photos showing what appeared to be at least seven dead children in the back of a pick-up truck. There were no visible traumatic injuries.
Another photo published by the group showed the bodies of at least 14 men, women and children on a street outside a hospital in Khan Sheikhoun.
The opposition-run health directorate in Idlib province, which is almost entirely controlled by rebel fighters and al-Qaeda-linked jihadists, says at least 70 people were killed, while the Syrian Observatory put the death toll at 72, including 20 children and 17 women.
However, some fear the death toll will rise, with the UOSSM saying at least 100 people had died and 400 others had suffered respiratory problems.
It was also not immediately clear whether anyone was killed when Khan Sheikhoun’s main hospital was struck by a rocket on Tuesday afternoon.
The source of the projectile was not clear, but the EMC said warplanes had targeted clinics and the headquarters of the Syria Civil Defence, whose rescue workers are known as the White Helmets.
The World Health Organisation said on Wednesday that the likelihood of a chemical being responsible was «amplified by an apparent lack of external injuries reported in cases showing a rapid onset of similar symptoms, including acute respiratory distress as the main cause of death».
«Some cases appear to show additional signs consistent with exposure to organophosphorus chemicals, a category of chemicals that includes nerve agents. »
The Organisation for the Prohibition of Chemical Weapons (OPCW) expressed serious concern about the reports and said a fact-finding mission was «in the process of gathering and analysing information from all available sources».
The OPCW will not be able to confirm anything until samples are tested at an accredited laboratory, but a doctor at a hospital in the town of Sarmin who treated some of the casualties believes it was the nerve agent Sarin.
«All the patients had the same symptoms — difficulty in breathing, weakness,» Dr Abdulhai Tennari told the BBC. «They had very huge secretions in their respiratory tracts, which induced suffocation. »
He noted that when the most serious cases were given an antidote for Sarin poisoning, atropine , their conditions became stable and they survived.
MSF said the patients’ symptoms were «consistent with exposure to a neurotoxic agent such as Sarin». Its medical teams also reported that victims smelled of bleach, suggesting they had been exposed to chlorine as well.
A Syrian military statement published by state media categorically denied the use of any chemical or toxic substance» in Khan Sheikhoun on Tuesday, adding: «It has never used them, anytime, anywhere, and will not do so in the future. »
Russia, which has carried out air strikes in support of President Assad since 2015, meanwhile said the Syrian air force had struck Khan Sheikhoun «between 11:30am and 12:30pm local time» on Tuesday, but that the target had been «a large terrorist ammunition depot» on its eastern outskirts.
«On the territory of the depot, there were workshops which produced chemical warfare munitions,» it added, without providing any evidence. «Terrorists had been transporting chemical munitions from this largest arsenal to the territory of Iraq. »
The ministry said the chemical munitions had also been used during the final stages of the battle for control of the northern Syrian city of Aleppo last autumn, asserting that the symptoms of the victims were «the same».
Hamish de Bretton-Gordon, a former commanding officer of the British Armed Forces Joint Chemical Biological Radiological Nuclear (CBRN) Regiment, said it was «pretty fanciful».
«Axiomatically, if you blow up Sarin, you destroy it,» he told the BBC.
«It’s very clear it’s a Sarin attack,» he added. «The view that it’s an al-Qaeda or rebel stockpile of Sarin that’s been blown up in an explosion, I think is completely unsustainable and completely untrue. »
Mr de Bretton-Gordon also noted that chlorine was the only chemical believed to been used in attacks in Aleppo over the past year.
A recent report by Human Rights Watch said government helicopters had dropped bombs containing chlorine on rebel-held areas of Aleppo on at least eight occasions between 17 November and 13 December, killing nine civilians.
