A Syrian army soldier is taken to hospital after an alleged chemical weapons attack near Aleppo in March. Photograph: George Ourfalian/Reuters  After months of negotiations, the United Nations has again announced that its experts will depart imminently for Syria to investigate alleged chemical weapons use.  The UN secretary-general, Ban Ki-moon, gave the green light after the Syrian government accepted arrangements for the investigation.  For the past two weeks, the two sides have been trying to agree on arrangements for the investigation.  Following Wednesday's agreement, UN deputy spokesman Eduardo del Buey said "the departure of the team is now imminent", but he provided no specific date. Two weeks ago the UN said the team would depart "within days".  The team is expected to visit three sites where chemical weapons attacks allegedly occurred, but diplomats and chemical weapons experts have raised doubts about whether they will find anything, since the alleged incidents took place months ago.  The mandate for the investigation is also limited. The team will report on whether chemical weapons were used, and if so which ones, but it will not determine the responsibility for an attack. This has led some commentators to question the value of the investigation.  President Bashar al-Assad's government initially asked the UN to investigate an alleged chemical weapons attack on 19 March in the village of Khan al-Assal, outside the embattled city of Aleppo, which was captured by the rebels last month. The government and rebels blame each other for the purported attack, which killed at least 30 people.  Britain, France and the US followed with allegations of chemical weapons use in Homs, Damascus and elsewhere. UN Middle East envoy Robert Serry told the security council last month the UN had received 13 reports of alleged chemical weapons use in Syria.  On 13 June, the United States said it had conclusive evidence that Assad's regime had used chemical weapons against opposition forces. That crossed what President Barack Obama had called a "red line" and prompted a US decision to send arms and ammunition to the opposition.  But agreement on a UN investigation was delayed for months because Syria wanted to limit the investigation to Khan al-Assal and the secretary-general, backed by the US, Britain and France, insisted on a broader investigation.  The UN gave approval for the investigation on 31 July following an "understanding" reached with Syria during a visit to Damascus by the UN disarmament chief Angela Kane and Swedish expert Ake Sellstrom, the team's leader, that three sites where chemical weapons were allegedly used would be investigated.  One site is Khan al-Assal, but the other two are being kept secret for safety reasons.  Under the agreement with Syria, the team will remain in the country for "up to 14 days, extendable upon mutual consent" to "conduct activities, "including on-site visits", del Buey said.  He said Ban believed an effective investigation of allegations can serve as "an important deterrent" against the use of chemical weapons.  Del Buey said "the overwhelming support of the international community for this investigation makes clear that the use of chemical weapons by any side under any circumstances would constitute an outrageous crime".
Syria and UN finally agree on terms of investigation, but analysts fear mandate is too limited and too late