Russia, UN seek 'workable humanitarian pause' in Aleppo amid reports of chlorine gas attack

The United Nations said Thursday it was trying to arrange with Russia a "workable humanitarian pause" in fighting in the divided Syrian city of Aleppo, warning time was running out for up to two million trapped civilians.

UN Special Envoy for Syria Staffan de Mistura said that reports of a gas, believed to be chlorine, being dropped on Aleppo are being investigated.

"There is a lot of evidence that it actually did take place", he told reporters, adding that if confirmed the attack would amount to a war crime.

• Syrian forces hit back at rebels in Aleppo
• Toxic gas dropped on Syrian town where Russian helicopter shot down, rescuers say

Russia said on Wednesday there would be daily three-hour ceasefires in Aleppo starting Thursday to allow humanitarian convoys to enter the city safely, a proposal which the United Nations mediator said was "not enough."

UN humanitarian adviser Jan Egeland said that a 48-hour pause was required to ensure safe deliveries, adding: "What is the new and positive thing today is that the Russian Federation said they would like to sit down with us and the other co-chair [the United States] to discuss how the UN proposal could be implemented. We are hopeful that will lead to something."

In Aleppo, a Syrian rescue worker and opposition activists said the attack on an opposition-held district killed at least two people. The attack, which took place late Wednesday on the city's eastern Zabadieh neighbourhood, saw at least four barrel bombs dropped on the area, one of which purportedly released the chlorine gas.

A Syrian military official denied the allegations, saying militants had fabricated the news. The official based in Damascus spoke on the condition of anonymity because he is not authorized to give official statements.

'Of great concern'

The Organization for the Prohibition of Chemical Weapons (OPCW) said Thursday that reports of possible chemical weapons use in Syria "are of great concern." The Netherlands-based agency said in a statement that the use of chemical weapons by anyone under any circumstances is "reprehensible," adding it continues to examine any credible reports it received.

Khaled Harah, a first responder in the rebel-held part of Aleppo, said a government helicopter dropped four barrel bombs and that one of them released chlorine gas, leading to the deaths of a mother and her two children.

The report, which was posted online on Thursday, could not be independently verified and it was not clear how it was determined that chlorine gas was released.

The Observatory, which tracks the civil war in Syria, also reported that government barrel bombs struck the neighbourhood. It had reports of two killed and several people suffering breathing difficulties but made no mention of chlorine gas.

Abdelkafi al-Hamdu, a resident of Aleppo, said he saw two airstrikes from his in-law's balcony, about 30 metres away. He said the first blast released a gas he identified by the smell as chlorine, but the wind was blowing in the other direction, lessening the odour.

He took cover in the apartment but began experiencing severe difficulties breathing, so he took his wife and daughter with him and tried to leave the building. But the odour grew stronger as they descended the stairs, so they returned to the higher floors to wait out the effects.

Accusations involving use of chlorine and other poisonous gases are not uncommon in Syria's civil war, and both sides have denied using them while blaming the other for using it as a weapon of war. Last week, the Syrian government and the opposition traded accusations of using chlorine, also in Aleppo.

Chlorine gas is a crude weapon, fatal in high concentrations while in lower doses, it can damage lungs or cause severe breathing difficulties and other symptoms such as vomiting and nausea.