A strong earthquake struck in a remote region of Botswana on Monday near the renowned Kalahari game reserve, sending shockwaves across the southern African country though there were no early reports of casualties or damage.

The magnitude 6.5 quake's epicentre was nearly 250 km (155 miles) north-northwest of the capital Gaborone at a depth of 12 km (7 miles), the US Geological Survey said.

Former US President George W Bush is due to visit the city on Tuesday to highlight the importance of America's overseas humanitarian aid, officials have said.

Anglo American said in email that there were "no reported safety incidents or damage to infrastructure" to any of its operations in Botswana caused by the earthquake.

Tremors were also felt in neighbouring South Africa.

"We certainly felt (the quake) here in central Gaborone. The buildings ... were trembling," said, Botswana's chief government spokesman, Jeff Ramsay.

"We don't have an reports of casualties or damage yet but its a bit early to tell."

Kgosi Kgomokgwana, the traditional chief of Moiyabana, a village close to the epicentre, said: "This is the first time we have felt something like that in this area."