(Bloomberg) -- Seven United Nations peacekeepers in the Democratic Republic of Congo were killed and seven others injured by members of the Allied Democratic Forces, a Ugandan Islamist rebel group.

“The peacekeepers died during the operation against ADF, which started on Tuesday in the territory on Beni,” Florence Marchal, spokeswoman for the UN mission known as Monusco, said Thursday by phone. “The operation against ADF is still going on.”

The militants killed one Tanzanian and six Malawian peacekeepers, Marchal said. Several Congolese soldiers and an unknown number of ADF fighters were also probably killed or wounded during the operation, according to an emailed statement by the UN secretary-general’s spokesman.

Congo, the world’s largest source of cobalt, has for more than 20 years struggled to defeat local and foreign militias in the east, which has deposits of tin, gold and coltan. The ADF has been active in Congo since 1993.

To contact the reporter on this story: Ignatius Ssuuna in Goma at issuuna@bloomberg.net

To contact the editors responsible for this story: Paul Richardson at pmrichardson@bloomberg.net, Eric Ombok, Helen Nyambura

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