ISTANBUL/KINSHASA, DR Congo

China on Thursday said it was working with the DR Congo government to locate "missing Chinese nationals" after an overnight attack at a gold mine left at least nine people dead.

Foreign Ministry spokeswoman Mao Ning said the armed attack on a private Chinese company "left several Chinese nationals dead or missing."

Rebels from the Cooperative for the Development of Congo (CODECO) militia group allegedly launched the attack on Wednesday in one of the gold mines in the Djugu area in the northeastern Ituri province.

According to natives of the area, six Chinese citizens and three Congolese soldiers were killed in the attack.

"China strongly condemns the attack," said Mao, adding that Beijing was "in close touch with" DR Congo over the attack.

"We ask the DRC to hunt down the perpetrators and bring them to justice as soon as possible, and take concrete and effective measures to better protect the safety and security of Chinese nationals and companies in the DRC."

Kololei Kailo, the chief of the region, attributed the attack to CODECO, a group of combatants who claim to defend the interests of the Lendu tribe against the rival tribe, the Hema.

Beijing acknowledged that the northeastern part of the DR Congo has long "suffered a poor security situation," according to an official transcript of the ministry’s regular news conference held Thursday.

"We once again remind our fellow Chinese nationals to closely follow the Foreign Ministry’s security alerts and act accordingly, not to travel to high-risk areas, and to leave those areas as quickly as possible if they are already there," said Mao.

Attacks on mining areas and relief convoys from UN humanitarian agencies occur regularly in Ituri and Kivu, in the north and southeast of DR Congo, as kidnappers loot money and other important things, but also demand a ransom to free the captives.