The Democratic Republic of Congo's (DRC) mines minister has called for a "genuine clean up" of South Kivu's mining sector.

Martin Kabwelulu issued the call after a Global Witness investigation reported by IBTimes UK in July revealed that up to $17m (£12.93m) of gold produced by Kun Hou Mining, a privately-owned Chinese company, went missing in the space of one year. That gold was likely smuggled out of Congo and into international supply chains.

The investigation also exposed the depths of corruption between armed groups, the artisanal gold trade and certain public officials in Shabunda territory, located in the South Kivu province, some 3,000km east of Kinshasa. During the peak of the boom in Shabunda in 2014, some $38m worth of gold was being produced, but the local hospital recorded over 500 cases of malnutrition.

The probe showed that the Chinese company supplied cash and weapons, including AK-47 rifles, to armed groups who in turn are alleged to have made up to $25,000 a month by extorting local miners.

In a letter to the governor of South Kivu on 24 August, Kabwelulu acknowledged "major problems" affecting "mineral supply chains causing fraud and smuggling of minerals". He added that mining officials who breached Congolese law should be prosecuted and restrictions placed on the company accused of acting illegally.

Global Witness has urged the governor of South Kivu to support Kabwelulu's letter in full and issue a swift and public response. "It's time to put words into action and make sure revenues generated from gold production go in to state coffers," said Sophia Pickles, a senior Global Witness campaigner.

"The population of Shabunda deserve to benefit from their own country's mineral wealth and not have it swindled away by corrupt officials and cowboy companies," she added.

Following the Global Witness report last month, the people of Shabunda held a two-day general strike, or "ville morte", to demand an investigation into the Chinese-owned company. Despite the local population's wishes and the findings of the report, Kun Hou Mining has been allowed to "operate freely".

Kabwelulu's letter commits to conducting an independent research mission to look into the report's findings and "includes a rare acknowledgement that high-ranking members of the Congolese army are preying on the mining sector in South Kivu".

"We know that Kun Hou are still present in Shabunda territory and have struck up a new deal with at least one mining cooperative in neighbouring Fizi territory," said Pickles. "Given the company's track record it's unclear why, almost a year after the national minister instructed that Kun Hou Mining be suspended, South Kivu's governor has allowed the company to continue its operations, and even to expand them".