Several witnesses told AFP that US troops fired on a crowd from the rooftops of the buildings.

Meanwhile, the death toll in Tuesday's shootings near the same buildings rose to 15 with 28 wounded, according to hospital sources.

US forces admitted partial responsibility for Tuesday's incidents, when witnesses also said American troops fired on a crowd, admitting on Wednesday that they had killed "around seven" of the victims.

"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," said Brigadier General Vincent Brooks at US Central Command's war base in Qatar.

On Wednesday, an AFP journalist saw two bodies arrive at the city's Al-Zahrawi hospital, where a doctor said eight people were also wounded. "Four bodies have just been brought in," Dr Riyadh Hamdi said.

Witnesses told AFP that US troops stationed on top of the government buildings had opened fire, but a US army spokesman would only confirm that an incident had taken place.

An Iraqi police officer, who had only just resumed duties after the overthrow of the Saddam Hussein regime last week, said his men had intervened in a bank raid when the Americans started shooting.

"A police patrol went to the bank to arrest the robbers. They fired a shot into the air and then the Americans, with the peshmergas (Kurdish fighters), fired on the civilians and the robbers," said Farsy Hasham, who arrived on the scene shortly after the incident.

Three policemen were injured, the officer in charge said. One of them, 21-year-old Mohammed Azad, said: "The police fired in the air to scare the robbers, later there were shots fired blindly at us from the governorate building," where the US troops were posted.

Another eyewitness, a civil servant who was driving police in his own car at the time, said: "The police knew there were robbers inside the bank. When they went in they arrested one robber but the other two got away.

"Outside, a crowd gathered to see what was happening and followed the police who were taking the robber towards the governorate.

"The Americans saw the crowd and started firing blind. I saw them with my own eyes. There were inside the building and on the roof. They did not let us take the injured," said Makhmud Ahmed, 31.

He said the bank was 500 metres (yards) from the local government building and the crowd was 100 metres away.

Yunes Yassin, a 28-year-old workman, interviewed separately, told a similar story of how the American troops opened fire, apparently thinking they were coming under attack.

"The police learned there was a bank robbery in progress and sent a patrol.

"Three cars arrived on the scene and the policemen entered the bank. A crowd had gathered in the square outside to watch when the shooting started, coming from the government building. I saw an American on the roof firing a machine-gun."

Omar Hassan, a 39-year-old civil servant, also said the shots came "from the roof of the government building where the Americans were".

The toll for Tuesday's clashes rose to 15. The earlier toll given by medical sources was 12 people killed and 60 wounded in clashes that took place near the same government buildings.

Najim al-Azzawi, deputy head of Al-Zahrawi hospital, confirmed those brought to the hospital were killed or wounded by machine-gun fire, while among the wounded four or five were in serious condition.

Witnesses claimed US troops fired shots as the crowd became increasingly hostile towards the new governor, Mashaan al-Juburi, who was making a speech they deemed too supportive of the US.

However, US troops guarding the governor said they opened fire after gunmen on an opposite roof began shooting.

SPACE.WIRE