Human Rights Watch (HRW) on Wednesday (August 30th) called for an independent enquiry to probe the fate of thousands of people who have disappeared in Syria's war and to identify mass graves, AFP reported.

More than 330,000 people have been killed and millions displaced, but HRW says the exact number of those missing could not be determined as most detention facilities were off-limits to outsiders.

"An independent institution in charge of investigating the fate and whereabouts of the disappeared, as well as unidentified human remains and mass graves in Syria, should be created immediately," the rights watchdog said.

HRW issued the appeal in a statement coinciding with the International Day of the Victims of Enforced Disappearances.

Last year, a team of UN experts raised the alarm over enforced disappearances and called for the situation to be referred to the International Criminal Court.

The watchdog said the enquiry "should have a broad mandate to investigate, including by reviewing all official records and interviewing any official".