Congo ? A powerful earthquake toppled homes onto children in eastern Congo, leaving an unknown number of casualties in a region already beset by war, poverty and volcanoes.

U.N. spokesman Michel Bonnardeaux said an unknown number of people were killed or injured as a result of Monday’s quake. Anne Edgerton, another U.N. spokesman in the region, said later that about a dozen injuries had been reported and no deaths could be confirmed.

The United States Geological Survey gave a preliminary measurement of 6.8 and located the epicenter about 6 miles below the surface of Lake Tanganyika, between Congo and Tanzania. Quakes of magnitude 7 can cause widespread and heavy damage.