Updated

Ivory Coast officials on Thursday began exhuming dozens of mass graves dating back to the country's 2011 postelection violence, as a new report accused President Alassane Ouattara 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 militant 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 as well as 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, meaning bodies were hastily buried in public places throughout the country, including at places of worship.

A government census identified 57 graves for exhumation in 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 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 Thursday, Human Rights Watch faulted 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. But Human Rights Watch said that while more than 150 supporters of former President Laurent Gbagbo have been charged in connection with the postelection violence, no Ouattara loyalists have been charged, fueling 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."

Ouattara defends his record. He said significant progress had been made in promoting equal justice, speaking on the BBC's "HARDtalk" program that first aired March 26. Asked specifically about a massacre in the western town of Duekoue where his fighters have been accused of killing hundreds of Gbagbo supporters, he said, "We have a report on what happened in Duekoue and all the people involved in the massacre in Duekoue have been taken to court."

Bolopion said there was no evidence to indicate that Ouattara's claim was truthful. "If the government has information that cases have been brought against people fighting for pro-Ouattara forces, we'll welcome that and we'll be happy to see the evidence that it's happening," he said. "But so far we have no reason to believe it's the case."

At Thursday's ceremony, victims said they hoped the exhumation of graves would help promote reconciliation even in the absence of balanced justice.

"When you think about cases where bodies were buried in houses and other places, the exhumation process will reduce the suffering of their parents and also reduce the desire for revenge," said Issiaka Diaby, president of a local victims' organization.

Fatime Alabi, 44, said she was looking forward to holding a proper funeral for her 17-year-old son, who was among the four men killed at the mosque.

"It's important to provide my son with a very good ceremony for his burial," she said. "I couldn't stand coming to the mosque every day and praying knowing that my son was buried here."