The injured have been taken to hospitals in Peshawar
At least 73 civilians were killed when an army jet bombed a remote village in Pakistan's tribal region of Khyber, a local official has told the BBC.
He said the incident took place on Saturday but news was slow in being reported because of the inaccessibility of the region.
The jet was involved in operations against Taliban militants in the nearby Orakzai tribal region.
Officials have reportedly already paid compensation to families of victims.
The military insists most of those killed were militants, but local sources say many civilians have also been killed.
Many people have died in air strikes in the area over the past 18 months.
Villagers say another strike - by a US drone missile - killed 13 people on Monday.
Military spokesman Maj Gen Athar Abbas told Associated Press news agency on Monday that those killed in the Pakistan army air strike were attacked because it had intelligence that militants were gathering at the site.
He denied civilians had died and said the victims were initially reported to be suspected militants, AP said.
Those on the ground gave a different version of events.
"All those killed were innocent civilians," the local administration official told the BBC.
"The dead include women and children. Dozens of people were also injured."
The official said he could not speak on the record as the military had put a "gagging order" on him to limit the fallout.
He said that initial information suggested that the jet had strayed away from the conflict zone and mistook the village for a militant compound.
Local officials have paid compensation amounting to more than $100,000 (£65,000) to the families of those killed, an unnamed official told the Associated Press news agency.
The BBC's Orla Guerin in Islamabad says this is a strong indication that local authorities, at least, believe a tragic mistake has been made.
The injured have been moved to hospitals in the nearby city of Peshawar. They are being treated under strict guard.
Police prevented a BBC correspondent from interviewing the injured at the Hayatabad medical complex in Peshawar.
Other reporters have also been denied access.
Correspondents say that the army is under heavy pressure from the US to move forcefully against Taliban and al-Qaeda militants in the north-west.
The army regularly reports killing militants in air strikes, but consistently denies it is responsible for civilian deaths.
Relief agencies say the offensives against militants in Pakistan and in neighbouring Afghanistan have displaced more than one million people.