(ALEPPO, Syria) -- U.S. officials do not believe that chemical weapons were used in Tuesday's attack in Aleppo, Syria.
U.N. Secretary General Ban Ki Moon announced on Thursday that the U.N. will investigate possible use of chemical weapons in the Syrian conflict. The announcement was welcomed by U.N. Ambassador Susan Rice, who said that the governing body should investigate "any and all credible allegations of the possible use of chemical weapons in Syria."
Syria is one of few countries who have not signed the Chemical Weapons Convention's agreement, which internationally bans use of chemical weapons. According to BBC News, Syria is believed to have large stockpiles of mustard gas and other chemical weapons.
The U.S. officials said that while nothing was certain, Tuesday's attack likely did not include use of any chemical warfare. However, tear gas or other chemical agents not categorized as chemical weapons could have been used, according to the officials.
At least one report said that Syrian rebels believed the agent to be Echothiphate, a chemical agent in insecticides. Echothiphate is not categorized as a chemical weapon.
"President Obama has been clear that the use or transfer of chemical weapons is totally unacceptable. 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," Rice said in her statement.
In addition to the Tuesday attack, rebels accuse the government of carrying out another attack involving chemical weapons near Damascus. There have been no verified instances of chemical weapon use in the two year conflict.
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