Aid agencies postponed a convoy of vital food and health supplies to Eastern Ghouta on Thursday (March 8th), as the Syrian regime pressed a relentless ground and air assault against the opposition enclave, AFP reported.
Dozens of people, including many children, were treated overnight for breathing problems and symptoms that medics said were consistent with chlorine attacks.
New airstrikes on the town of Zamalka killed at least seven civilians, according to the Syrian Observatory for Human Rights, bringing the total number of dead in the offensive to more than 900.
The aid trucks were meant to bring relief to war-weary civilians living under government siege for five years and now facing a deadly Russian-backed assault.
The fighting has prompted international outrage, culminating in the UN Security Council demanding an immediate ceasefire, aid deliveries and evacuations.
But with bombardment continuing, a joint convoy between the UN, International Committee of the Red Cross and Syrian Arab Red Crescent planned for Thursday could not go through.
"The convoy for today is postponed, as the situation is evolving on the ground, which does not allow us to carry out the operation in such conditions," ICRC spokeswoman Ingy Sedky said.
It marks the second time this week that aid operations have been disrupted by military developments, with food deliveries cut short Monday due to bombardment.
At one medical facility in the town, doctors treated at least 29 patients with signs of exposure to chlorine, according to the Syrian American Medical Society (SAMS), which supports hospitals in Eastern Ghouta.
It said victims were suffering from shortness of breath, wheezing, and redness of the eyes, all symptoms consistent with a toxic attack.
Regime forces have been repeatedly accused of using chlorine on Eastern Ghouta in recent weeks, which both the government and Russia have staunchly denied.