A new report says a United Nations-backed military effort has failed to subdue Rwandan Hutu rebels in the eastern Democratic Republic of Congo.

In a report for the U.N. Security Council, researchers say the offensive by Congolese and U.N. forces has only made life worse for civilians in Congo's North and South Kivu provinces.  The report says the fighting and related violence has displaced hundreds of thousands of people.

A coalition of human rights groups made similar claims last month, saying more than 1,000 civilians have been killed since the offensive began in January.

The offensive targets the FDLR, a group of ethnic Hutu fighters, many of whom fled Rwanda after the 1994 genocide.

U.N. researchers say the FDLR is funding its operations through the illegal mining of gold and cassiterite, a material used in many cell phones.

The U.N. has about 17,000 peacekeepers in Congo, providing food, fuel, medical and transportation support to Congolese government soldiers.

Congo's government is still trying to assert control over North and South Kivu, more than six years after the end of a brutal civil war.

Various rebel groups and militias continue to operate in the area, despite repeated attempts by the army and U.N. forces to stabilize the region.  Efforts to integrate rebels into the army have been only partially successful.