The International Crisis Group warned that a political conflict that was simmering in Ivory Coast since November bore the hallmarks of civil war. Ivorian leader Laurent Gbagbo refused to step down despite international recognition that Alassane Ouattara won the November contest meant to unite a country divided by civil war in 2002.
Investigators with the United Nations said they believed a series of mass graves uncovered near the commercial capital Abidjan was related to an April 12 massacre pitting Gbagbo's supporters against fighters loyal to Ouattara, CNN International reports.
Roughly 68 bodies were recovered from the 10 mass graves uncovered.
"Some of these crimes may amount to crimes against humanity," Ravina Shamdasani, spokeswoman for the U.N. High Commissioner for Human Rights, was quoted as saying. "But for now, we can't say that with confidence."
At least 1,000 people were killed in Ivorian violence related to the contested November election. Around 200 bodies were recovered from a mass grave in April.
Ouattara was formally sworn in Friday.