"I can confirm there were heavy bombardments," Andiwal told Reuters by phone from Helmand.
"We have heard of heavy casualties too and have sent a team to investigate this."
Dan Nolan, Al Jazeera's correspondent in Kabul, said: "It does appear there were a large amount of civilians killed and injured."
He said Afghan government sources had said a public execution of a suspected spy carried out by the Taliban had been taking place when the aircraft struck.
Haji Hakim Jan, 27, said he lost four of his brothers in the attack.
"I had another brother of mine and an eight-year-old sister wounded in the bombing," he said
He said he believed the deaths would alienate civilians from Western troops and make people join the Taliban.
If confirmed, the deaths would be the highest civilian casualties caused by foreign troops since the overthrow of the Taliban government in 2001.
The US military said in a statement late on Thursday that coalition forces had conducted a "precision" air raid against two "notorious Taliban commanders" conducting a leadership meeting in a remote area of the Baghran district on Thursday.
It said the fate of the pair was unknown.
Residents and an official said the bombings occurred as a huge crowd of people had gathered to watch the execution by Taliban fighters.
A Taliban spokesman said there was no public execution and those killed were all civilians attending a ceremony at a shrine.
There was no independent verification of the reported accounts from either side.
More than 350 civilians have been killed in operations by foreign forces this year in Afghanistan, according to government officials and aid workers.