The gathering followed the announcement Sunday of the arrest of three Chinese nationals found in possession of gold bars and large sums of cash, according to South Kivu Governor Jean-Jacques Purusi.

Local authorities in the resource-rich province say hundreds of mining companies, mainly Chinese, extract gold without declaring profits and often without valid operating permits.

"South Kivu (province) minerals should serve the development and well-being of communities," read one banner held aloft at the demonstration seen by an AFP reporter and called by pro-democracy movements and unions.

In July, the local government launched a crackdown on the mining companies deemed not in compliance with Congolese law and suspended their activities.

The east of the country boasts abundant underground reserves of gold, diamonds and minerals used notably to manufacture mobile phones and electric cars.

The mineral riches are in contrast with the conflicts which have scarred the region for three decades. They have worsened with the resurgence at the end of 2021 of the M23 rebel group, which Kinshasa blames Rwanda for supporting.

In late 2022, the DRC attempted to break what it termed the export circuit of minerals to Rwanda by awarding a monopoly on regional gold exports to the Emirati-Congolese producer Primera Gold.

But lacking sufficient liquidity, the firm has struggled to curb the black market, according to the Bureau of Scientific and Technical Studies (BEST), a Congolese NGO specialising in mining governance issues.