Colonel William Mayville acknowledged that his forces were responsible for mortar fire that killed an Iraqi boy during a major Muslim holiday, the Eid al-Fitr, as his family picnicked in the northern oil region of Kirkuk.
Mayville told a meeting with local government officials, attended by an AFP correspondent, that he had ordered an investigation into the shelling that also wounded the boy's mother and two siblings.
He said his troops had opened fire because they suspected insurgents were in the area, but that those responsible for the deadly error would be held accountable.
Family to sue
Mayville added that he ordered the payment of $2500 in compensation for the family of the nine-year-old boy, Basssam Sami Awwad, and $1500 for each of the three injured.
But it was not enough for the grief-stricken family, who told AFP they will sue for compensation in the Kirkuk courts.
"We will never let this matter rest, especially as my child was a boy who had nothing to do with the violence in Iraq. He was just playing with his brothers when it happened," the boy's father, Sami Awwad, 31, said.
Meanwhile, the death toll from Sunday's attacks on Eid al-Adha celebrations at the offices of the two main Kurdish Iraqi political parties in the northern town of Arbil rose to at least 101, the US military said.
A spokesman added that 133 of the injured remained in hospital three days after the carnage.
The twin Arbil bombings now mark the deadliest post-war attack in Iraq. They outstrip a car bombing in the southern holy city of Najaf last August which killed a leading Shia politician, Ayat Allah Muhammad Baqir al-Hakim, and more than 80 other people.
About 101 people were killed and
133 injured in Arbil bombings
Brigadier General Mark Kimmitt, deputy operations chief of the US-led occupation forces in Iraq, said on Tuesday that FBI forensic teams had begun sifting through the debris in Arbil.
He added that foreign fighters were probably to blame.
Leaders of the two Kurdish political groups targeted in Arbil, 350km north of Baghdad, have also said the attacks could be the work of the insurgent group, Ansar al-Islam.
The group, which controlled an enclave of northeast Iraq before being crushed by US forces at the end of March, is suspected of having with al-Qaida.
"We will never let this matter rest, especially as my child was a boy who had nothing to do with the violence in Iraq. He was just playing with his brothers when it happened"
Father of dead Iraqi child
For more than a decade, the Kurdistan Democratic Party (KDP) and the Patriotic Union of Kurdistan (PUK) have controlled the semi-autonomous north, but their demands for virtual autonomy have angered other ethnic groups.
Many suspect opponents of Kurdish political ambitions of having a hand in the attacks.
A top Shia leader has suggested that a multi-member presidential body could ease tensions between Iraq's different ethnic communities once the US-led occupation force cedes power, as scheduled by 30 June.
"Everyone should be reassured, we want to reassure them all and we want everyone to participate actively in this period until a constitution is drafted and elections are held," Abd al-Aziz al-Hakim said.
Al-Hakim, the head of the largest Shia organisation, the Supreme Council for the Islamic Revolution in Iraq (SCIRI), said the Kurds' demand for virtual autonomy should be settled by a constitution and a popular vote.
Meanwhile, two civilians were wounded when a mortar attack on US troops sparked high explosive artillery fire in response near the restive western Iraqi town of Ramadi, the US military said.
A spokesman was unable to confirm whether the casualties were wounded by American fire or mortar shrapnel.