There was no claim of responsibility for the bombing in the province of Ghazni but officials blamed the blast on the "enemies of Afghanistan".

"The bus was travelling from Kabul to Kandahar. Along the road near Ghazni city it struck a roadside bomb. Five people were killed and 11 others were injured," provincial police chief Zarawar Zahid told AFP.

Baz Mohammad Hemat, a doctor in the local hospital, confirmed the casualties.