Local officials on Tuesday said civilians came under attack when US planes bombed the Waigal valley in Nuristan province, about 170km northeast of Kabul, for several hours late last week.
"Eight people, all members of Ghulam Rabbani's family, were killed," Nuristan security commander al-Haj Ghulam Allah Nuristani said.
Rabbani was the former governor of Nuristan before the Taliban seized power in 1996.
Nuristani said a lot of houses were destroyed in the bombing, as they were built close together on the mountainside.
The Afghan official, however, failed to say whether the houses were bombed intentionally or by mistake.
"Eight people, all members of Ghulam Rabbani's family, were killed"
Al-Haj Ghulam Allah Nuristani,
Nuristani said Afghan officials had brought the matter to the notice of US officials.
"We are in negotiations with them. We have had a couple of meetings," he said, adding the interior minister would contact the US military about the bombing.
US military spokesman Colonel Rodney Davis said he was unable to confirm whether there were any civilian casualties.
The US-led force had faced accusations of bombing civilian targets even earlier. Eight nomads were killed in a raid in Zabul province in September.
Another raid in April killed eleven civilians when their house was struck by a 45-kg laser-guided bomb in southeast Paktika province.