UN Secretary-General Ban Ki-moon (R) speaks to media reporters prior to his meeting with Ake Sellstrom (L), head of the UN chemical weapons investigation, at the UN headquarters in New York, on April 29, 2013. UN Secretary-general Ban Ki-moon on Monday voiced his "complete confidence" in the UN fact-finding mission on the alleged use of chemical weapons in Syria, while urging the Syrian authorities to allow the investigation to proceed "without delay and without any conditions." (Xinhua/Niu Xiaolei)

UN Secretary-General Ban Ki-moon (R) speaks to media reporters prior to his meeting with Ake Sellstrom (L), head of the UN chemical weapons investigation, at the UN headquarters in New York, on April 29, 2013. UN Secretary-general Ban Ki-moon on Monday voiced his "complete confidence" in the UN fact-finding mission on the alleged use of chemical weapons in Syria, while urging the Syrian authorities to allow the investigation to proceed "without delay and without any conditions." (Xinhua/Niu Xiaolei)

UN Secretary-General Ban Ki-moon (R) speaks to media reporters prior to his meeting with Ake Sellstrom (L), head of the UN chemical weapons investigation, at the UN headquarters in New York, on April 29, 2013. UN Secretary-general Ban Ki-moon on Monday voiced his "complete confidence" in the UN fact-finding mission on the alleged use of chemical weapons in Syria, while urging the Syrian authorities to allow the investigation to proceed "without delay and without any conditions." (Xinhua/Niu Xiaolei)

UN Secretary-General Ban Ki-moon (1st R) speaks to media reporters prior to his meeting with Ake Sellstrom (L), head of the UN chemical weapons investigation, at the UN headquarters in New York, on April 29, 2013. UN Secretary-general Ban Ki-moon on Monday voiced his "complete confidence" in the UN fact-finding mission on the alleged use of chemical weapons in Syria, while urging the Syrian authorities to allow the investigation to proceed "without delay and without any conditions." (Xinhua/Niu Xiaolei)