A powerful earthquake hit the Lake Tanganyika area of central Africa and was felt as far away as the Kenyan coast Monday. The United States Geological Survey said its 6.8 measurement was preliminary and located the epicenter in the area of Lake Tanganyika, between Congo and Tanzania. Henri Burgard, UN spokesman in the Congolese town of Uvira, said the quake lasted 30 seconds. "The buildings shook quiet strongly. We have no reports of deaths so far," he said. Workers in buildings in downtown Nairobi left their offices in a panic. The quake was also felt in Mombasa, on Kenya's coast. Quakes of magnitude 7 can cause widespread and heavy damage.