A fact-finding mission of the global anti-chemical weapons watchdog has found indications that some people in Syria were exposed to deadly sarin gas, or a compound like it, according to a report the United Nations released on Monday.The findings come in the latest monthly report on Syria from the Organization for the Prohibition of Chemical Weapons (OPCW) chief Ahmet Uzumcu. UN Secretary-General Ban Ki-moon attached it in a Dec. 29 letter to the 15-nation Security Council.Uzumcu's report said his agency's fact-finding mission in Syria was looking into charges by the Syrian government that chemical weapons were used in 11 instances. The report did not specify when the alleged toxic gas attacks occurred."In one instance, analysis of some blood samples indicates that individuals were at some point exposed to sarin or a sarin-like substance," Uzumcu said. "Further investigation would be necessary to determine when or under what circumstances such exposure might have occurred."The Syrian government has long accused opposition fighters, who have been seeking for nearly five years to oust the country's president, of using chemical weapons. Western-backed rebels in Syria have repeatedly denied using chemical weapons.Western officials say it is unlikely rebels would have the capability to deploy sarin gas.