The quake spread out from a spot near the eastern side of Lake Tanganyika, which forms the border between Tanzania and the Democratic Republic of Congo, and struck at 1219 GMT, the Observatory of Earth Sciences in the French city of Strasbourg said.

The exact coordinates were 6.9 degrees on the southern latitude and 30.8 degrees longitude east, near the Tanzanian village of Sibwesa.

"The epicentre was located some 10 kilometres underground, it's therefore possible that the tremor was widely felt," said a seismologist at the French observatory, Christophe Deperetti.

He added that a quake of such magnitude "is relatively rare in that region, which is not in an area where big tectonic plates meet."

The last big temblor to hit that part of Africa was in October 2000, when a quake measuring 6.7 was recorded.

There were no immediate reports of damage or casualties after the latest geological shudder, though residents of the Kenyan capital of Nairobi, 900 kilometres (560 miles) distant, reported feeling the tremor, which prompted the evacuations of some tall buildings that swayed.

A US observatory, the US Geological Survey, registered the strength of the quake at 6.8 on the Richter scale, according to its website.

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