There was no claim of responsibility for the bombing in the province of Ghazni but officials blamed the blast on the "enemies of Afghanistan", a standard phrase used to refer to the Taliban.

"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.