Britain and France have told the United Nations secretary-general they have reliable evidence that the Syrian government has used chemical weapons near Aleppo, in Homs and possibly in Damascus.
The British and French ambassadors told Ban Ki-moon in a letter on March 25 that soil samples and interviews with witnesses and opposition figures backed their belief that the government used chemical shells that had caused injuries and deaths, UN diplomats and officials said.
Syria asked Ban Ki-moon on March 21 to investigate an alleged chemical weapons attack by rebels two days earlier on Khan al-Assal village in northern Aleppo province. The rebels blamed regime forces for the attack.
The following day, Britain and France asked the UN chief to investigate allegations of chemical weapons use in two locations in Khan al-Assal and the village of Ataybah in the vicinity of Damascus, all on March 19, as well as in Homs on December 23.
Syrian soldiers were reportedly killed and injured in the Khan al-Assal incident but the British and French believe this was the result of a misfired Syrian government shell, the diplomats and officials said.
After examining the letters from Syria and the Europeans, the secretary-general appointed a team of chemical weapons experts to investigate the allegations in Khan al-Assal and in Homs, where there was the most evidence. But the Syrian government has so far refused to allow the experts to go anywhere but Khan al-Assal.
The secretary-general said the team of experts, nonetheless, would proceed with "its fact-finding activities." He said additional information has been requested from the three governments.
UN diplomats say the chemical weapons experts are expected to visit camps for Syrian refugees, neighbouring countries where Syrians have fled and possibly London and Paris to try to obtain information outside Syria. The diplomats spoke on condition of anonymity because details have not been announced.
British Foreign Secretary William Hague told Parliament last week that the government "is increasingly concerned that there is evidence of the use of chemical weapons in Syria."
"We welcome the UN secretary-general's announcement of an investigation into the allegations and again call on the Syrian regime to cooperate fully and allow the investigation unfettered access to all areas," he said. "They should take heed that the world is watching and those who order the use of chemical weapons or participate in their use must be held to account."