The US-led coalition admitted Tuesday its soldiers shot and killed a local Baghdad official in Sadr City, a volatile Shia neighborhood where clashes have already claimed the lives of US troops.
Violence also shook the southern capital of Basra where at least eight Iraqi civilians were wounded when a bomb exploded, the local police chief said.
The shooting of a hand-picked US official in an area that houses as many as two million Shiites and has been a source of troubles for the Americans was sure to inflame the critics of the US presence in Iraq.
Mohannad Ghazi al Kaabi, the US-appointed official for Sadr City, died from wounds Sunday after troops shot him when he refused to follow security procedures for entering Sadr City's municipal building, the US military said in a statement.
"During the altercation, a shot was fired, wounding Mohannad in the lower extremities," the US military said in a statement, adding that an investigation had been launched.
One US soldier was shot dead by gunmen during clashes in Sadr City in mid-October. That attack was suspected of being carried out by followers of young Shiite cleric Moqtada Sadr, who has been a vocal critic of the Americans.
Already in August, US forces clashed with Sadr's followers after a US helicopter tried to knock down an Islamic flag hanging above the neighborhood. One Iraqi teenager was killed in the fighting and others were wounded.
Sadr City, known as Saddam City under the former regime, was renamed for Moqtada Sadr's family of revered clerics when Americans entered the city in April.
Insurgents, thought linked to ousted president Saddam Hussein, have already gunned down several pro-American public servants in the last month.
The shooting also came at a moment when Moqtada Sadr appeared to be stepping back from his previously bellicose stance against US forces, issuing a statement last week where he urged the country's 15-million strong Shiite majority to find common ground with the coalition.
Elsewhere, at least eight Iraqi civilians, some of them children, were wounded when a bomb exploded in the centre of Basra on Tuesday, Colonel Mohammed Khazim al-Ali said.
"Some are seriously wounded but we have no dead so far," the head of internal security forces in Iraq's southern capital said.
All the injured had been taken to hospital, the colonel added, blaming Saddam loyalists for the blast.
A British military jeep was damaged in a bomb blast on Sunday.
And an American soldier and a Kurdish fighter working with the Iraqi border guard died in separate incidents, the US-led coalition said Monday, as it vowed not be deterred by attacks.
The top US general for Iraq, John Abizaid, also met Saturday with tribal and religious leaders from western Anbar province, a bastion of resistance to the Americans which spans from the Syrian border to the powderkeg towns of Fallujah and Ramadi.
The daily violence directed against US troops in the province of 1.5 million people was at the centre of the talks, said an aide to Fallujah mayor Taha Hamid Bdaywi who attended the meeting.
There was no immediate confirmation from the US military.
But in a get-tough message to the insurgents, the coalition called in air strikes over the weekend around Fallujah and deposed dictator Saddam's hometown of Tikrit, marking the first such bombardments since the six-week springtime war.