A videotape has been broadcast which purports to show before-and-after footage of a wedding which Iraqis say the US bombed, killing about 40.
The video showed decorated vehicles driving in the desert
The film, released by a US news agency, combines a wedding home movie with video of the aftermath of the attack, which the US says targeted militants.
Some victims and survivors appear to be present in the wedding video.
The US has insisted it was responding to fire from foreign fighters near the border with Syria.
However, the chief US military spokesman in Iraq conceded on Saturday that a celebration may have been taking place at the site.
"Bad people have parties too," said Brig Gen Mark Kimmitt.
Associated Press Television News says it cannot confirm the authenticity of the video of the celebrations in Makr al-Deeb, a desert hamlet near the town of Qaim.
The agency says the material broadcast was taken from several hours of footage, apparently filmed by a hired photographer who was among those killed.
An organist who appears on the video of wedding celebrations...
The film shows gleaming pick-up trucks - some decorated with ribbons - speeding through the desert apparently en route to the wedding.
The celebrations themselves feature the traditional firing of salutes from guns and singing as well as men dancing to the music of a popular wedding singer.
The singer, Hussein Ali, was also killed, his grieving family told the BBC shortly after the attack.
... seems to appear in a burial shroud, apparently dead, in film taken after the attack
Clearly visible on the wedding footage is a man playing electric organ who later appears to be among the corpses filmed by APTN.
AP says a reporter and a photographer who interviewed more than a dozen survivors a day after the bombing were able to identify many of them on the wedding party video.
It also says its footage of the aftermath shows remnants of musical instruments, pots and pans, and festive brightly coloured bedding.
Survivors told journalists the wedding party had ended and guests were in bed when bombing began in the early hours of Wednesday.
Brig Gen Kimmitt suggested the site had been "somewhat of a dormitory" housing "military-aged" men.
Another US official told reporters on Monday that a wedding may have been held at the scene several hours before the air strike.
"We still don't believe that there was a wedding or a wedding party going on when we hit in the early hours of the morning," the unidentified official was quoted as saying by Reuters news agency.
"Could there have been some sort of celebration going on earlier? Certainly."
The BBC's Caroline Hawley reports from Iraq that, whatever the truth of why the US bombed Makr al-Deeb, it has been a public relations disaster.
Images of the funerals of the victims - and now the apparent video of the wedding itself - have been shown on television around the Arab world and beyond.