Syria has agreed to allow UN investigators to visit three sites where chemical weapons have allegedly been used.
A statement from Secretary General Ban Ki-moon's office said that the UN inspectors will go to Syria as soon as possible.
Some 27 people were killed in attacks allegedly involving chemical weapons in the northern town earlier this year, the BBC reports.
Moon had demanded that the UN wanted to investigate allegations of chemical weapons use since the 28-month conflict began in Syria.
However, the Syrian government has until now been insisting the UN probe be limited to Khan al-Assal.
