France is consulting its partners over how to respond to growing proof of the use of chemical weapons in Syria, says French Foreign Minister Laurent Fabius.
"There is increasingly strong evidence of localised use of chemical weapons," Fabius said yesterday at a meeting of European Union foreign ministers. "That must all be verified, we are doing that with other partners.
"We are consulting with our partners to see what concrete consequences that we are going to draw from this."
He was speaking after French newspaper Le Monde said it had first-hand accounts that forces loyal to Syrian President Bashar al-Assad had repeatedly used chemical weapons against rebel fighters in Damascus.
Le Monde, in a report on its website yesterday, said one of its photographers had suffered blurred vision and respiratory difficulties for four days after an attack on April 13 on the Jobar front, inside central Damascus.
Assad's government and the rebels have accused each other of using chemical weapons. United Nations investigators have been ready for weeks, but diplomatic wrangling and safety concerns have delayed their entry into Syria.
Undercover in and around the Damascus area for two months alongside Syrian rebels, a Le Monde reporter and photographer said they had witnessed battlefield chemical attacks and had also talked to doctors and other witnesses of their aftermath.
They describe men coughing violently, their eyes burning, their pupils shrinking.
"Soon they experience difficulty breathing, sometimes in the extreme; they begin to vomit or lose consciousness. The fighters worst affected need to be evacuated before they suffocate," Le Monde wrote.
"Reporters from Le Monde witnessed this on several days in a row in this district, on the outskirts of Damascus, which the rebels entered in January."
Syria, which is not a member of the anti-chemical weapons convention, is believed to have one of the world's last remaining stockpiles of undeclared chemical arms.
"In two months spent reporting on the outskirts of the Syrian capital, we encountered similar cases across a much larger region. Their gravity, their increasing frequency and the tactic of using such arms shows that what is being released is not just tear gas, which is used on all fronts, but products of a different class that are far more toxic," Le Monde wrote.
This month, Carla Del Ponte, a member of a UN inquiry commission looking at alleged war crimes in Syria, said it had gathered testimony from casualties and medical staff indicating that rebel forces had used the banned nerve agent sarin. Western governments have said they had no such evidence.
Syria's revolt began with peaceful protests in March 2011 inspired by Arab uprisings elsewhere. Assad's violent response to the unrest eventually led to an armed insurgency.
At the Brussels meeting, European Union nations struggled to overcome deep divisions on whether to ease sanctions against Syria to allow arms shipments to the rebels.
Additional reporting by Associated Press