Warning: The following videos contain distressing and graphic images
New videos show the eyewitness accounts of four men who witnessed an alleged chemical attack on Zamalka, a suburb of Damascus.
One man describes a "strange smell" while another says people died while trying to escape to upper floors of a building to get away from the gas.
'We started smelling a strange smell'
"Around 2 after midnight we felt three rockets hit the area. They didn't have loud explosions but more like the normal mortar attacks.
"We went down to check and we started smelling a strange smell. Then the men started shouting 'It's a chemical attack!'
"As I was trying to get to the lads, more shelling started. Then I fell on the stairs and was unconscious. But the lads picked me up and took me to my sister's flat.
"Thankfully I was saved. They gave me injections and oxygen and eye drops and they managed to save me in time.
"The next morning we found each family in their home as they were, dead in each house. All had foaming at the mouth, and some from the eyes. Some had blood from their ears.
"Some had tried to fight it but the children were all dead instantly, you could tell.
"Later we buried around 150 bodies in mass graves in this area. I helped to bury them."
'People died trying to reach upper floors of buildings'
"People started hearing from the mosques that they have to go to move to higher buildings[to escape the gas]," says this man.
"They found this abandoned building and they ran up to the upper levels, but they were already affected.
"So those people died while they were trying to go up. Today we found them here."
"They didn't manage to escape it quick enough.
"We found more than 40 bodies since yesterday and the search is still on. If you come with us we can show you more."
'The shelling started at 2am when people were sleeping'
"After the chemical attack yesterday we found the remains of this rocket here today," says this man.
"We found these empty rocket shells, and we may still find more.
"We witnessed all those people who were martyred and the physical effects it had on people.
"We opened many houses in this area and we found the families dead. The shelling started at 2.05am - people were sleeping, there was no electricity, no calls.
"Most people weren't aware it was a chemical attack until a majority of the people had died."
"We heard 12 rockets. But the sound of the explosion wasn't huge or scary. They didn't sound like rockets that we have heard before."
Grandfather desperately looking for daughter
This man is looking for his daughter in the aftermath of suspected chemical attacks on Damascus suburbs.
He says he has already found the dead bodies of two of her children. Her son was 12 years old and her daughter was eight. He lost his nephew too.
A translation is scarcely needed; his devastation is clear.