Iraqi police also were searching for an American journalist who was kidnapped Saturday.
BAGHDAD, Iraq -- Two suicide bombers disguised as police infiltrated the heavily fortified Interior Ministry compound in Baghdad and blew themselves up Monday during celebrations of National Police Day, killing 29 Iraqis.
The attackers died before getting near the U.S. ambassador and senior Iraqi officials at the festivities, but the blasts capped a particularly deadly week for American and Iraqi forces.
Iraqi police also were searching for an American journalist who was kidnapped Saturday by gunmen who ambushed her car and killed her translator in Baghdad.
Jill Carroll, a 28-year-old freelancer for The Christian Science Monitor, was seized in Baghdad's predominantly Sunni Arab al-Adel neighborhood. Police said she went there to see a Sunni Arab politician.
The escalating violence after the Dec. 15 parliamentary elections -- at least 498 Iraqis and 54 U.S. forces have been killed -- came as Iraq's electoral commission again delayed releasing the results of the vote.
An Internet site known for publishing extremist material from al-Qaida in Iraq leader Abu Musab al-Zarqawi carried a claim of responsibility for Monday's suicide attack, saying it was in revenge for the torture of Sunni Arab prisoners at two detention facilities run by the Shiite-led Interior Ministry.
"The lions of al-Qaida in Iraq were able to conduct a new raid on the Interior Ministry, taking revenge for Allah's religion and the Sunnis, who are being tortured in the ministry's cellars," the statement said.
The claim, which could not be independently verified, referred to reports that more than 100 abused prisoners were recently found in the jails -- bolstering complaints by Sunni Arabs about the treatment of detainees by Interior Ministry forces.
Another purported al-Zarqawi statement rebuked Sunni Arabs for participating in the parliamentary elections, saying they had "thrown a rope" to save U.S. policy.
Meanwhile, the U.S. military said eight U.S. troops -- including four Alaska Army National Guard members -- and four American civilians died aboard a U.S. Army Black Hawk helicopter that crashed Saturday in northern Iraq.
The military initially said only that eight passengers and four crew were aboard.
Sunni Arabs also expressed anger over a raid Sunday by U.S. troops on the Umm al-Qura mosque, Baghdad headquarters of the Association of Muslim Scholars, a Sunni clerical group that is believed to have ties to some insurgent groups.
The mosque is in the al-Adel neighborhood, one of Baghdad's roughest and the same area where the American journalist was kidnapped.
A U.S. military official, speaking on condition of anonymity because of the sensitivity of the situation, said the raid was a necessary immediate response to the kidnapping based on a tip provided by an Iraqi citizen. The military said Sunday that six people were detained. No other details were released.
"The violations of the occupation forces are continuing and they are endless. The raid on the Um al-Qura mosque is the most recent example," said Muthana Harith al-Dhari, a spokesman for the clerical group.
The suicide attack on the sprawling Interior Ministry compound came after a particularly deadly four-day period for Americans, with 28 killed since Thursday, including 24 troops.
At least 498 Iraqis have been killed, including 355 civilians and 143 security forces, and 54 U.S. troops have died since the Dec. 15 elections. With the latest military deaths, at least 2,207 U.S. service members have died since the war started in 2003, according to an Associated Press count.
The bombs exploded in quick succession about 1,500 feet from the parade being watched by U.S. Ambassador Zalmay Khalilzad, Interior Minister Bayan Jabr, Defense Minister Sadoun al-Dulaimi and hundreds of others.
None of the officials was hurt and the ceremony was not interrupted, said Lt. Col. Barry Johnson, a U.S. military spokesman. He said the explosions "had no impact on the ceremony and did not require anybody to take cover."
The first bomber was shot by the police, but his explosives detonated. A second bomber detonated his explosives. One bomber was wearing the uniform of an Iraqi police major and the other was dressed as a lieutenant colonel. Both had passes that enabled them to get through checkpoints and into the compound.
At least 29 people were killed and 18 wounded, mostly policemen, said Ala'a Abid Ali, an official at al-Kindi hospital.
In political developments, officials canceled a news conference during which they had hoped to give out more preliminary election results, saying they were still auditing returns from about 50 ballot boxes and wanted to announce everything at once.
Election results will be released after Eid al-Adha, said Hussein Hindawi, of Iraq's electoral commission. It was the second time they had postponed releasing information on the election -- which Sunni Arab groups said was tainted by fraud.
The results are expected to show the religious Shiite United Iraqi Alliance with a strong lead. The Shiites will, however, need to form a coalition government with support from Kurdish and Sunni Arab political groups.
In other developments:
-- Ibrahim Bahr al-Uloum, who resigned as oil minister last week over increases in consumer fuel prices, also resumed his old post after the prime minister and president asked him to do so, Iraq's Council of Ministers said.
-- Gunmen assassinated an investigative judge in Kirkuk.
-- Five bodies, bound and blindfolded, were found shot to death in Baghdad late Sunday.
-- A car bomb exploded west of Baqouba on Monday, killing two civilians.
Associated Press writers Jason Straziuso and Sinan Salaheddin in Baghdad contributed to this story.