Three bodies have been found in Congo's Central Kasai province two weeks after two UN experts and their colleagues disappeared there, the government said.
Congolese spokesman Lambert Mende told Top Congo FM that the bodies were found on Monday, but did not confirm if they were Michael Sharp of the United States and Zaida Catalan of Sweden.
"To our knowledge, there are no other foreigners who have disappeared in this region," Mr Mende said, adding that the provincial commissioner was on his way to recover and identify the bodies.
Mr Sharp's father, John Sharp, wrote on his Facebook page on Monday that the bodies of two Caucasians were found in shallow graves in the search area for the UN experts.
"Since no other Caucasians have been reported missing in that region, there is a high probability that these are the bodies of MJ and Zaida," he wrote.
"Dental records and DNA samples will be used to confirm the identities. This will take some time.
"All other words fail me."
A UN spokesman in New York said the U.N. was analysing the remains and could not confirm the identities of the dead as yet.
Mr Sharp, Ms Catalan, interpreter Betu Tshintela, driver Isaac Kabuayi and two motorbike drivers went missing March 12 in Central Kasai while looking into recent large-scale violence and alleged human rights violations by the Congolese army and local militia groups.
Their disappearance is the first time UN 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 security forces 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 UN.