Besides Kenya and Congo, tremors were felt in Burundi, Rwanda and Tanzania, impoverished countries connected by a string of lakes and mountains, many of them active volcanoes.

Residents of Kalemie, an eastern Congolese town on the shores of Lake Tanganyika with a population of 200,000 people, reported at least one death and several injuries and said mud-brick houses had collapsed in poor neighbourhoods.

"A child died when the house he was in collapsed during the earthquake. Several other people have broken limbs and are in hospital. We'll see in the hours that come if more come to hospitals," Kalemie community leader Fidel Muteba said.

It was the first fatal seismic event in the region since 2002 when Africa's deadliest eruption in 25 years swept away thousands of homes and killed 25 people after the 3,469-metre (11,380-foot) Mount Nyiragongo exploded near the eastern Congo town of Goma.

Hundreds of people evacuated office buildings in the centre of Nairobi on Monday after the tremors and the streets were clogged with people trying to drive away from the city centre.

"People came running down - scared - because you don't know what it is. You're moving this way and that," said Tabitha Nyambati, demonstrating how the tremor made her sway.

"We actually saw the building shaking and seats moving in the building," said Peter Ragula, 37, a Nairobi salesman.

"People were saying they were dying I thought I was sick at first, I thought I was very dizzy, but I realised seats were moving and I realised there must have been a problem."

The USGS site said a 6.5 magnitude quake hit close by in October 2000, injuring seven people and causing little damage.

NOT MUCH TO DESTROY

"A quake of this kind could easily produce significant damage, but I wonder what kind of infrastructure they have there in the region. There may not have been much to destroy," said Dr Andrzej Kijko, head of seismology unit at South Africa's Council for Geoscience.

Officials in Tanzania said the tremor was felt there but that they had received no reports of any injuries.

"We felt a tremor at about 3:20 p.m., but that is all we've had. I have no reports on injuries or damages in my region," said Abdalah Mssika, regional police commander for the Shinyanga region bordering Lake Victoria.

The quake was also felt in the Rwandan capital Kigali, and by residents in Burundi's capital of Bujumbura.

"We felt the ground shake," Bujumbura taxi driver Simeon Nduwimana told Reuters by telephone, adding that the situation was now normal and he had not seen any damaged buildings.

In Kigali, internet cafe attendant Abdul Hamidou said: "The desktop screens were moving, my chair was shaking making me feel dizzy, and all of a sudden I saw customers running out."

"We all felt it and came out of the building. I was seated on my chair and felt it moving, things were shaking everywhere," said a civil servant in Bukoba in Tanzania's Kagera province.