The governor of Helmand province, Gulab Mangal, and the provincial chief of Afghan intelligence escaped unhurt, said an official statement, and the group attended the funeral of Ahmed Wali Karzai in neighbouring Kandahar province.
Mangal and the Helmand chief of the National Directorate of Security intelligence agency were travelling together when the bomb exploded in the neighbouring province of Kandahar, where Wali Karzai was killed yesterday.
The bomb was detonated by remote-control in the Maiwand district, wounding two soldiers attached to the NDS detached unit, the governor's office said.
Cheaply made roadside bombs are the weapon of choice for the Taliban, fighting a nearly 10-year insurgency against Afghan and foreign forces that has been largely focused in the southern heartlands of the country.
President Hamid Karzai buried his younger half-brother in a family cemetery in the southern suburbs of Kandahar city, after the regional powerbroker was shot dead a day earlier by a guest in his home