The two UN officials and four Congolese nationals accompanying them were kidnapped on Sunday in the conflict-ridden province of Kasaï-Central, the United Nations said on Monday.
The DRC government suspects that the group had travelled to the province by motorcycle and were stopped at a bridge and abducted by unidentified individuals near the Ngombe village.
A spokesperson said they were investigating the disappearance and criticized the UN.
“It's not normal for people to come here and start moving around like this,” said Lambert Mende.
“If the government had been informed of the activities of these officials, perhaps they would have had an escort for their safety.”
The New York Times writes that the group were investigating reports of human rights violation after a video appeared to show soldiers opening fire on at least a dozen civilians during a counterinsurgency operation.
A spokesperson for the Swedish foreign ministry told The Local this week they had no new information.
“There is a Swede being looked for in Congo. Bu we won't go into details about how the search is going,” said Patric Nilsson on Tuesday.
The Swedish foreign ministry has since 2006 advised against travelling to the DRC, where there is a conflict between security forces and militias.