The six marines died Monday in Haditha, 140 miles northwest of Baghdad. A seventh marine was killed Monday by a car bomb in Hit, 50 miles southwest of Haditha in the volatile Euphrates River valley.
At least 1,801 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to the Associated Press.
In other violence, a roadside bomb targeting a U.S. military convoy exploded Tuesday at the entrance to a tunnel in Baghdad, and at least 29 civilians were wounded.
The continuing violence comes as political pressure mounts ahead of the publication of the country's proposed constitution. U.S. Ambassador Zalmay Khalilzad ratcheted up pressure on the draft committee Tuesday, calling for the new Iraq constitution to protect women's rights. As the August 15 completion deadline approaches, Khalilzad and other American officials have faced significant pressure from several women's rights groups to ensure the Iraqi group drafting the document limit the role of Islam in the constitution.
The ambassador said that the U.S. government expects a constitution that would ensure full rights to all Iraqis.
"My focus is to help get a constitution that does this," he said. "Of course, the Iraqis will decide but we will help in any way we can."
Women's rights groups say a section on civil rights in the draft constitution gives prominence to strict Islamic Sharia law and would significantly roll back women's rights under a 1959 civil law enacted by a secular regime.
Under Sharia law, women would inherit only half of what men receive. In issues of marriage and divorce, women would be at a significant disadvantage since only men would have the legal power to initiate divorces.
In addition to issues surrounding Sharia law, ethnic divisions also threaten to derail the constitutional process. Kurdish leaders have said they are prepared to withdraw their support of the charter if it does not satisfy their concerns on several issues, including expanding of the geographic breadth of their autonomy, and reversing years of expulsions and ethic killings in formerly Kurdish areas, the New York Times reported.
As Khalilzad works to influence Iraqi politicians on the constitution, he has also publicly outlined the process for a gradual American troop withdrawal, according to the New York Times.
Khalilzad said the American military would hand over control of specific areas to Iraqi forces and "withdraw its own units from these areas," he said in a news conference Monday. Iraqi forces have been given sole control of very few areas of the country so far.
He declined to say which cities U.S. soldiers would leave, but said he had formed a committee with Iraqi leaders to create a withdrawal plan.