A spokesman for the Multi-National Force-Iraq confirmed to The Associated Press that the helicopter had crashed. He said five had died, and the bodies of two soldiers who had originally been missing were found.
The spokesman said hostile fire was not suspected.
The official spoke on condition of anonymity because he wasn't authorized to provide details.
The chopper was a part of an aerial convoy flying from Kuwait to the U.S. military base at Balad just north of Baghdad. The Chinook, the Army's workhorse, is designed to transport troops and supplies to combat and other regions.
The statement said the incident was under investigation. Separately, a U.S. soldier died of noncombat-related causes on Wednesday, and an investigation into the cause of death was under way, the military said.
On Wednesday, gunmen killed a Sunni assistant to the governor of one of Iraq's most volatile provinces, the latest in a series of attacks that have marred the Islamic holy month of Ramadan in Iraq.
Shamil Younis, an engineer who handled technical affairs for Gov. Duraid Kashmola, was killed in a drive-by shooting as he was walking home after finishing prayers at a nearby mosque in Mosul, police said. The attack occurred shortly after iftar, the meal that breaks the sunrise-to-sunset fast during Ramadan.
The governor, also a Sunni, confirmed the slaying and promised an investigation. He called it "a brutal crime against this innocent, good man."
Kashmola, who is the governor of Ninevah province, of which Mosul is the capital, himself survived an apparent assassination attempt this summer.
The June 26 car bombing struck near the site where Kashmola was inspecting damage from an earlier explosion that police believed was meant to lure him to the market area in Mosul. At least 18 people were killed in the attack.
Nobody claimed responsibility for the killing of Younis, but it comes as insurgents - most of them Sunnis - are making a stand in Mosul, 360 kilometers (225 miles) northwest of Baghdad, after being routed in Baghdad and other urban centers.
Violence has dropped dramatically in Iraq since last year, but a wave of attacks coinciding with Ramadan shows that insurgents retain the ability to strike.
The deadliest attack on Wednesday was a double car bombing in western Baghdad, which killed at least eight people and wounded 20, a police officer said.
The U.S. military gave a lower casualty toll, saying three Iraqi civilians were killed and 15 others wounded.
Elsewhere in Baghdad, a roadside bomb at an intersection killed three people and wounded six, police said. The policemen spoke on condition of anonymity because they were not authorized to speak to the media.
U.S. military officials have warned that the security gains are fragile and urged Iraqi leaders to take advantage of the relative calm to make progress on the political front.
Iraqi lawmakers, however, failed to agree Wednesday on a new U.N. proposal aimed at breaking the deadlock over a law paving the way for provincial elections, which the U.S. considers key to building peace among the country's rival religious and ethnic communities.
The balloting has been delayed due to Kurdish objections to power-sharing proposals for oil-rich Kirkuk, which Kurds want to annex into their semiautonomous region.
The U.N. issued a plan that would enable elections to be held in all provinces except Tamim, which includes Kirkuk, and creating a seven-member committee to study the issue, lawmakers said. But Arabs and Turkomen raised new objections, calling for a deadline to be imposed on the committee and for the removal of the presidential council from the process.
The parliament approved a provincial elections law earlier this year despite a Kurdish boycott, but it was vetoed by President Jalal Talabani, himself a Kurd, and his two deputies.
Parliament adjourned until Thursday, when it will try again to overcome the impasse. The United Nations has warned further delay could prevent the balloting from being held this year.
Iraqi Interior Ministry spokesman Maj. Gen. Abdul-Karim Khalaf, meanwhile, said a military operation in Diyala province, northeast of Baghdad, was making progress and could end in about two weeks. He also said 15 suspects had been arrested in connection with a suicide bombing that killed 22 people on Monday in the Diyala town of Balad Ruz, 45 miles (70 kilometers) northeast of Baghdad.
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Associated Press writers Hamid Ahmed, Sinan Salaheddin and Mazin Yahya in Iraq and Robert H. Reid in Amman, Jordan, contributed to this report.
