The US military has denied allegations that its forces in Iraq killed dozens of people celebrating a marriage in the west of the country.
A funeral for those reportedly killed in the US raid was held in Ramadi
Initial reports suggested that a wedding party near the Syrian border was the target of a US air strike.
A US military spokesman confirmed that about 40 people had been killed in the area - but said US forces had targeted a safe house used by foreign fighters.
He said coalition forces had retaliated after coming under attack.
The incident occurred late on Tuesday at the village of Makr al-Deeb, near the border town of Qaim.
"We took hostile fire and we returned fire," said Brigadier General Mark Kimmitt, deputy director of
operations for the US military in Iraq.
He said there were no indications that the victims of the attack were part of a wedding party.
He added that a large amount of money, Syrian passports and satellite communications equipment had been found at the site of the attack.
The US, which is facing ongoing insurgency in Iraq, has long said that foreign fighters are entering the country from Syria.
Arab TV channel al-Arabiya, quoting eyewitnesses, said a frontier village was attacked by helicopter gunships before dawn.
The incident apparently happened after wedding guests in the village started firing in the air in celebration, the report said.
One man told al-Arabiya: "The US planes dropped more than 100 bombs on us."
"They hit two homes where the wedding was being held and then they levelled the whole village."
Television pictures from Makr al-Deeb show many bodies being taken for burial, the dead included young children.
The BBC's Nick Childs in Washington says that right or wrong, those reports could be hugely damaging to the US-led coalition.
US forces have been accused before of killing innocent people in both Iraq and Afghanistan after mistaking the celebratory gunfire at wedding parties - traditional in many Arab countries - for attacks on them.
In 2002, nearly 50 people at a wedding in Afghanistan were killed in a US air strike.