A State Department cable suggests the Syrian army likely used chemical weaponsduring an attack in the city of Homs last month, Foreign Policy's The Cable reports.

According to the website, a cable signed by the U.S. consul general in Istanbul and sent to the State Department described an investigation by the consulate into the Dec. 23 attack.

An Obama administration official who reviewed the document, which was classified at the "secret" level, detailed its contents to The Cable. "We can't definitely say 100 percent, but Syrian contacts made a compelling case that Agent 15 was used in Homs on Dec. 23,