U.S. army soldiers from B Company, 1st Battalion, 23rd Infantry Regiment patrol an area of west Baghdad's Ghazaliyah neighborhood on Friday alongside their Iraqi colleagues. The U.S. Army continued operations throughout the dangerous Sunni Arab area of Ghazaliyah on Friday.

Baghdad, Iraq ? Striking at the Iraqi government’s highest-ranking Sunni Arab, a suicide bomber blew himself up among worshippers at the deputy prime minister’s home Friday, seriously wounding the leader and killing at least nine people in a security breakdown that shook the image of a calming Baghdad.

Salam Al-Zubaie underwent surgery to remove shrapnel from his abdomen at a U.S.-run hospital. Prime Minister Nouri al-Maliki, head of the Shiite Muslim-dominated government, said his deputy was in serious but stable condition and wouldn’t need treatment abroad “for now.”

The bombing, coming just a day after a Katyusha rocket slammed to earth 50 yards from visiting U.N. Secretary-General Ban Ki-moon, starkly emphasized the continuing chaos in Iraq even after the introduction of thousands more American soldiers and six weeks of an extensive security crackdown in the capital.

Inside job alleged

An Iraqi military spokesman, Brig. Qassim al-Moussawi, called the suicide bombing an inside job, telling state television that an al-Qaida fighter had infiltrated al-Zubaie’s security detachment.

Al-Moussawi offered no details, and repeated calls to his office to verify the claim went unanswered. The Interior Ministry, which oversees Iraq’s police forces, said it had no information on that claim.

Al-Maliki aide Mariam Taleb al-Rayes also told al-Sharqiyah television the attacker had “infiltrated” al-Zubaie’s inner circle, but did not elaborate. She added that the bomber’s car blew up outside the house seconds after he detonated his explosives vest.

The bomber attacked al-Zubaie a day after a statement purportedly posted on the Internet by an al-Qaida umbrella group noted him as a stooge “to the crusader occupiers.”

Group claims attack

Hours after the assassination attempt, the same group, the Islamic State in Iraq, claimed responsibility for the bombing and said it was reporting the “good news that our troops were able, with God’s will, to target” al-Zubaie.

“We tell the traitors of al-Maliki’s infidel government, wait for what will destroy you, you will never be safe, with God’s will on the Iraqi soil, as long as we have a blinking eye and a beating heart,” said the statement. Its authenticity could not be independently verified.

Harith al-Dhari, head of the Association of Muslim Scholars, a militant Sunni group with suspected links to insurgents, appeared to endorse the attempt on al-Zubaie’s life.

“It indicates a huge security failure and a success by the resistance,” al-Dhari told al-Jazeera television. “The bigger event here is that the resistance was able to deliver a message to all politicians telling them: ‘Don’t speak on our behalf.'”

Al-Zubaie’s loss would be a blow to the government, but the al-Maliki administration would not be derailed. There is no legal requirement the post be filled by a Sunni Arab – only an informal agreement among the political parties that formed the current government, and leaders would likely be able to find another Sunni if necessary.

‘Reprehensible’ act

The bomber detonated an explosives vest after weekly prayers in a small mosque attached to al-Zubaie’s home near the Foreign Ministry, just north of the capital’s heavily guarded Green Zone.

Pools of blood, shredded draperies, broken glass and a tangle of splintered wood littered the floor. The walls were pockmarked from shrapnel.

Harith al-Obeidi, a Sunni lawmaker, said the dead included al-Zubaie’s brother, a cousin, his personal secretary and the imam of the private mosque. He said 17 people were wounded – five critically.

Ball bearings packed in the explosives vest remained lodged in al-Zubaie’s chest, but surgeons decided against trying to remove them, said Dhafer al-Ani, another Sunni lawmaker.

In Washington, White House Spokesman Tony Snow condemned the attack as a “completely reprehensible act” that “demonstrates that there are some terrorists who will do whatever they can to disrupt things.”

U.S. Ambassador Zalmay Khalilzad promised the United States would work with the Iraqi government and security forces to capture those behind the bombing.

Many politicians targeted

If the Islamic State in Iraq, an organization linking al-Qaida in Iraq and several other Sunni extremist groups, was responsible for the attack, that might signal a growing concern within al-Qaida about recent success by U.S. troops in Anbar province, where some Sunni insurgent groups and tribes have turned against al-Qaida.

Such a high-profile attack could dampen support for the American inroads in Anbar, which has been an insurgent stronghold west of Baghdad.

Al-Zubaie is among a long list of politicians – Sunnis, Shiites and Kurds – who have been targeted by militants seeking to undermine a succession of U.S.-backed governments in Iraq. Close relatives of government officials have also been victims of assassinations, abductions and roadside bombs.