(Reuters) - The world's chemical weapons watchdog is confident it will be able to meet deadlines to destroy Syria's toxic stockpile even though some sites are in disputed or rebel-held territory, a special adviser to the organization's director general said.

Inspectors from the Hague-based Organisation for the Prohibition of Chemical Weapons (OPCW), which won the Nobel Peace Prize last week, have visited nearly half of more than 20 sites declared by Damascus, Malik Ellahi, special adviser to Director General Ahmet Uzumcu, said on Thursday.