China has condemned a militia attack in the Democratic Republic of Congo that killed some of its citizens, and called for the perpetrators to be hunted down, the foreign ministry said on Thursday.

The comments followed media reports, citing sources, that four Chinese nationals were killed in the attack at a mining site in the central African nation's gold-rich northeastern province of Ituri.

The foreign ministry said Wednesday's attack by armed forces on a Chinese-funded private enterprise led to the death and disappearance of several Chinese citizens.

China is in close communication with DRC authorities in the search for those missing, ministry spokesperson Mao Ning told a regular press briefing.

"We urge the DRC to pursue and punish the perpetrators in accordance with the law as soon as possible," Mao said, while calling for measures to beef up security and protection for Chinese citizens and enterprises there.

"Those already in high-risk areas should be evacuated as soon as possible," she added.

The long-term security situation in the northeastern region of the DRC was grim, Mao added, with the ministry having issued several security warnings.

Wednesday's was the latest deadly militia attack in a region where the violence is linked to long-running competition for influence and rich mineral resources.