BAGHDAD - 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 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.

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, following the introduction of thousands more American soldiers and six weeks of an extensive security crackdown in the capital.

Growing U.S. voter disenchantment with the war, now in its fifth year, prompted a narrowly divided House of Representatives to vote Friday to order the withdrawal of combat troops next year in Congress' boldest challenge to Bush administration policy. President Bush said he would veto the measure if it passed the Senate and reached his desk.

An Iraqi military spokesman, Brig. Qassim al-Moussawi, called the sucide 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 singled him out as a stooge “to the crusader occupiers.”

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 attack on al-Zubaie.

“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.'”

In Washington, White House Spokesman Tony Snow condemed 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.

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.

Last month, Vice President Adel Abdul-Mahdi, a Shiite, narrowly escaped an assassination attempt.

In other violence Friday, four people were killed in a bombing in Baghdad, and police reported finding 34 apparent victims of sectarian killings nationwide, 25 of them in the capitol. The U.S. military said an American soldier was killed by a roadside bomb in western Baghdad and a Marine died in combat in Anbar province on Thursday.