Suspected militiamen have kidnapped five workers, including one French national, a Tanzanian and three Congolese, at Banro Corp's Namoya gold mine in eastern Democratic Republic of Congo, the company said on Thursday.

The attack took place during the night of Tuesday into Wednesday and an investigation is underway, Crispin Mutwedu, a senior Banro official, told Reuters, adding that a local militia has been threatening the mine recently.