Ivorian authorities have begun exhuming dozens of mass graves dating back to the country's 2011 post-election violence.
The exercise started on Thursday as a new report accused Alassane Ouattara, Ivory Coast's president, of failing to bring his supporters to justice for crimes they allegedly committed during the conflict.
Justice Minister Gnenema Coulibaly presided over the exhumations, observing a moment of silence at the site before digging started at the first grave on the grounds of a mosque in Abidjan's Yopougon district.
The grave contained the bodies of four men aged 17 to 35, who were killed at the height of the violence in April 2011 while defending the mosque against supporters of former President Laurent Gbagbo.
More than 3,000 people died over a period of five months after Gbagbo refused to concede defeat to Ouattara in the November 2010 election.
Addressing religious leaders and relatives of the men who died at the mosque, Coulibaly said "the prevailing security situation" during the conflict made proper funerals impossible for many families.
A government census identified 57 graves for exhumation in the commercial capital Abidjan alone, many of which contain multiple bodies.
The graves together are believed to contain more than 400 bodies. The exhumation process will eventually extend throughout the country, Coulibaly said.
Yopougon was a flashpoint during the violence, and Coulibly said 36 of the 57 graves identified in Abidjan were located in the district.
The violence continued in Yopougon for weeks after Gbagbo was arrested from a bunker following military intervention by France, Ivory Coast's former colonial master, and the United Nations.
Coulibaly said the exhumations would provide closure to victims' families while offering valuable information that would help bring perpetrators of crimes to justice.
But in a report released on Thursday, Human Rights Watch criticised judicial officials for failing to come up with a strategy to investigate grave crimes committed during the conflict.
Fighters on both sides committed atrocities, including the extrajudicial killings of hundreds, a national commission of inquiry reported last August.
Human Rights Watch said that while more than 150 supporters of former President Laurent Gbagbo had been charged in connection with the post-election violence, no Ouattara loyalists have been charged, fuelling allegations of "victor's justice".
A "Special Investigative Cell" formed to undertake criminal investigations appears to be understaffed, and its authority has been called into question when it has attempted to probe crimes committed outside Abidjan, the report said.
Ouattara's repeated promises to hold all perpetrators of grave crimes to account "are starting to ring hollow", said the rights group's U.N. director Philippe Bolopion.
"Our fear is that if impunity continues, the cycle of violence in Ivory Coast will not really be broken," he said.
"And sadly we will not be surprised if in a few years from now we see another cycle of violence, with the same perpetrators in position to commit the same types of crimes."