A US commander has admitted that American troops did shoot and kill a number of Iraqis during a protest in the northern city of Mosul.
A 14-year-old boy is driven away from Wednesday's shootout
Brigadier-General Vince Brooks said US marines and special forces soldiers fired at demonstrators on Tuesday after they came under attack from people shooting guns and throwing rocks.
"Fire was indeed delivered from coalition forces, it was lethal fire and some Iraqis were killed as a result, we think the number is in the order of seven and we think there were some wounded as well," he said.
A BBC correspondent in the city says Mosul is extremely tense.
There was further gunfire on Wednesday with at least three people killed and around 17 wounded, hospital officials said.
Police reportedly fired into the air to disperse looters who were trying to rob a bank.
Eyewitnesses said US troops then fired on a crowd close to the building from nearby rooftops.
However, one marine told the Associated Press news agency the troops were responding to fire from a building across a park.
US forces had earlier denied responsibility for the killings on Tuesday.
Witnesses said US troops fired into a crowd growing increasingly hostile to a speech being given by the town's newly appointed governor.
A US spokesman said troops were returning fire from a nearby building and did not aim into the crowd.
Mosul is tense, correspondents say
The incident underlines the difficulties US forces face in trying to keep the peace in a country now confronting an uncertain future.
Some reports suggest up to 15 people were killed in Mosul, with between 60 and 100 people injured.
The trouble began as an angry crowd gathered outside the governor's building, demanding that Kurdish peshmerga fighters and Americans leave the city, witnesses told the BBC.
Mosul's new governor, Mashaan al-Juburi, appears to have tried to pacify the crowd.
Some witnesses said the US troops then began shooting after children threw stones, others that the first firing was not from American weapons.
Details are also emerging of revenge attacks which apparently took place in the days following the withdrawal of Iraqi troops from Kirkuk, also in the north.
The human rights organisation, Human Rights Watch, says at least 40 Baath party officials were the targets of reprisal killings.
The organisation has also expressed concern over the plight of about 2,000 Arabs who say they were forced to leave their villages around Kirkuk.
They were settled there in the 1970s as part of the Iraqi Government's campaign to "Arabise" the area.
Massoud Barzani, leader of the Kurdistan Democratic Party, has condemned any attacks on Arabs by Kurds.