An RFA correspondent, who was himself slightly injured in the blast, says a provincial official is among the wounded.
The device exploded in the village of Hisarak in the eastern province of Khost during the funeral of Hakim Taniwal, the governor of neighboring Paktia Province who was killed in a suicide attack on September 10.
The Taliban has reportedly claimed responsibility for Taniwal's death.
A government delegation had come to Hisarak from Kabul to attend the governor's funeral.
The delegation left the area by helicopter after the blast.