At least 17 Iraqis have died in a US air strike on the city of Falluja, hospital officials have said.
Correspondents say the US air strike left two vast craters
Reports say the dead included three children and a woman.
US officials say the strike was a deliberate, "precision" attack aimed at followers of the wanted militant Abu Musab al-Zarqawi.
Mr Zarqawi has been accused of leading the violent Sunni Muslim resistance to the US-led coalition in Iraq and the interim Iraqi government.
Zarqawi's group is believed to be linked to al-Qaeda and to have been responsible for numerous attacks and suicide bombings - often targeting Iraqis working with the US-led coalition.
'Torn to pieces'
The AFP news agency says two buildings were destroyed when a US fighter jet hit a target in the southern Jubail district of Falluja on Wednesday night.
"We have received 17 dead people and six wounded, several in serious condition", said Doctor Seifeddin Taha, from the Falluja general hospital.
"All the wounded are families. Among the dead, there could be two or three children but the bodies are torn to pieces and it's difficult to tell," he told the AFP news agency.
Witnesses told the AP news agency the strike hit a residential house in the southern neighbourhood of the city.
Correspondents describe two giant craters in the ground, with one house completely destroyed and the second badly damaged.
A US military statement, quoted by the AP agency, said the strike was a "precision" attack on a militant safe house.
It said the raid was undertaken based on various Iraqi and coalition intelligence sources, after Zarqawi associates allegedly executed someone earlier on Wednesday.
"The Zarqawi associates were observed removing a man from the trunk of a car, executing him then burying his body," the military said.
US officials have offered a $25m bounty for information leading to the capture of Zarqawi.
Falluja, about 40 miles (65km) west of Baghdad, in the so-called Sunni triangle, has been a flashpoint city and centre of some of the strongest resistance to coalition forces.
In April US marines pulled back after a three-week siege of the city. Hundreds died and thousands fled the city as US forces and Iraqi insurgents fought in built up civilian areas.