UNITED NATIONS — The United Nations will investigate the possible use of chemical weapons in Syria, which would amount to a crime against humanity, Secretary-General Ban Ki-moon announced Thursday.
The investigation could be broader than the Syrian government's request for an independent probe of a purported chemical weapons attack on Tuesday. Ban said he was aware of other, similar allegations and hoped the probe would ultimately help secure Syria's chemical weapons stockpile.
U.N. spokesman Martin Nesirky said France and Britain sent a letter to the secretary-general Thursday asking for an investigation of three alleged chemical weapons attacks. He said Ban will review this suggestion as the U.N. develops the mandate for the investigation.
Syria is widely believed to have a large stockpile of chemical weapons. The government has not confirmed it, saying only that it would never use chemical weapons against its own people.
"My announcement should serve as an unequivocal reminder that the use of chemical weapons is a crime against humanity," the secretary-general said. "The international community needs full assurance that chemical weapons stockpiles are verifiably safeguarded."
Western nations fear President Bashar Assad would use chemical weapons if he sees the two-year civil war turning against his government. But they are equally concerned that rebel forces, including some linked to al-Qaida, could get their hands on unguarded chemical weapons or the materials to make them.
Ban said investigators would look into Syria's allegation that rebels carried out a chemical weapons attack on Khan al-Assal village in northern Aleppo province.
The rebels denied the attack and blamed regime forces. The Syrian National Coalition, the main opposition group, also demanded an international investigation.
The secretary-general said he was aware of "other allegations of similar cases involving the reported use of chemical weapons," but did not make clear whether these would be part of the U.N. investigation.
France and Britain, in their letter to the secretary-general obtained by The Associated Press, raised allegations of chemical weapons use in two locations in Khan al-Assal, the village of Ataybah in the vicinity of Damascus, and in Homs on Dec. 23. It asked the U.N. chief to launch "an urgent investigation into all allegations as expeditiously as possible."
U.S. Ambassador Susan Rice said the United States "supports an investigation that pursues any and all credible allegations of the possible use of chemical weapons in Syria." She said the U.S. will continue to work closely with its partners to obtain further information on allegations of potential or actual use, and underscored the importance of launching the investigation swiftly.
"President Obama has been clear that the use or transfer of chemical weapons is totally unacceptable," she said. "If Bashar Al-Assad and those under his command make the mistake of using chemical weapons, or fail to meet their obligation to secure them, then there will be consequences. Those responsible will be held accountable."
Ban said his senior advisers are working to set up an investigation in close consultation with the Organization for the Prohibition of Chemical Weapons, known as the OPCW which oversees the Chemical Weapons Convention, and the World Health Organization. He said issues to be decided include the overall mandate, the composition, and operational conditions, including safety and security.
The investigation will start "as soon as practically possible," Ban said, but "will not happen overnight."
Nesirky said the OPCW and WHO have the technical expertise needed for an investigation, adding that there are "technical reasons for being on the ground sooner rather than later."
The OPCW said in a statement that it was ready to work closely with the U.N. in setting up and conducting the mission.
"While allegations of this nature are not new to conflict situations, they are nonetheless serious, especially in the context of Syria which is not a state party to the Chemical Weapons Convention," the OPCW said. "This remains a matter of serious concern."
Ban said full cooperation from all parties will be essential and stressed that this includes "unfettered access," a point he would emphasize in a letter to the Syrian government.
The secretary-general said that if requested by a U.N. member state, he has the authority under General Assembly and Security Council resolutions to authorize an investigation of an alleged chemical weapons attack. Nesirky said there are precents for such investigations, in Azerbaijan and Mozambique in 1992.
As the situation in Syria worsens, Ban said, "the international community's concern about the safety and security of chemical weapons stockpiles as well as possible use by all parties has increased."
Ban said he has spoken out repeatedly on the Syrian government's primary responsibility to ensure the safety and security of any chemical weapons and sent two letters to President Bashar Assad "to remind him of this solemn duty."
"It is my hope that the mission would contribute to ensuring the safety and security of chemical weapons stockpiles in Syria," he said.
With more than 70,000 people killed and no end to the violence in sight, the secretary-general reiterated that "the military solution in Syria is leading to the dissolution of Syria."
He called on the deeply divided region and international community to find unity and support efforts by the joint U.N.-Arab League envoy Lakhdar Brahimi to help the Syrian people reach a political solution and end the conflict.