The bodies of an American and a Swedish investigator with the United Nations and their Congolese interpreter were found in Central Kasai province, authorities said Tuesday, more than two weeks after they disappeared while looking into recent violence there.

"After tests ... it is possible to identify the bodies as the two U.N. experts and their interpreter as being found near the Moyo river," Congo government spokesman Lambert Mende said. Investigations will continue to seek other missing Congolese colleagues, he said.

Michael Sharp of the United States and Zaida Catalan of Sweden, along with interpreter Betu Tshintela, driver Isaac Kabuayi and two motorbike drivers, went missing March 12 while looking into large-scale violence and alleged human rights violations by the Congolese army and local militia groups.

Congo's police inspector general, Charles Bisengimana, said the bodies were found Monday between the cities of Tshimbulu and Kananga, the provincial capital.

The confirmation came a day after Sharp's father, John Sharp of Hesston, Kansas, wrote on his Facebook page that the bodies of two Caucasians had been found in shallow graves in the search area, saying there was a high probability the dead were his son and his son's colleague.

"All other words fail me," he wrote.

U.N. Secretary-General Antonio Guterres said the world body would conduct an inquiry into what happened to the two experts. He said the cause of their deaths hadn't yet been determined.

"Michael and Zaida lost their lives seeking to understand the causes of conflict and insecurity in the DRC (Congo) in order to help bring peace to the country and its people," Guterres said in a statement, sending his condolences to their families.

Sharp and Catalan's disappearance is the first time U.N. experts have been reported missing in Congo, Human Rights Watch has said, and it is the first recorded disappearance of international workers in the Kasai provinces.

Parts of Congo, particularly the east, have experienced insecurity for decades, but violence in the Kasai provinces in central Congo represents a new expansion of tensions.

The Kamwina Nsapu militia has been fighting security forces since last year, with the violence increasing after government troops killed the militia's leader in August. More than 400 people have been killed and more than 200,000 displaced since then, according to the U.N.

When asked earlier Tuesday whether the investigators' disappearance could be a turning point in the U.N. sending experts to the region, Guterres' deputy spokesman, Farhan Haq, said: "We hope that we could continue to send experts to do their necessary monitoring activities wherever they need to go. Of course, that needs to be undertaken with full respect and understanding of the security condition on the ground."