An Apache helicopter also went down today after coming under fire in a predominantly Shiite area in eastern Baghdad, but both crew members were safely evacuated, the military said.

President Bush's nominee to head the Joint Chiefs of Staff, meanwhile, acknowledged that slow progress in Iraq is hurting America's credibility and emboldening Iran's regional ambitions.

While steady progress has been made on the military front, Iraq's political factions have made only limited headway in achieving reconciliation, said Navy Adm. Michael Mullen, who has been nominated to replace U.S. Gen. Peter Pace as the nation's top military officer.

Iraq's parliament shrugged off U.S. criticism and adjourned for a month, as key lawmakers declared there was no point waiting any longer for Prime Minister Nouri al-Maliki to deliver Washington-demanded benchmark legislation for their vote.

Speaker Mahmoud al-Mashhadani closed the final three-hour session Monday without a quorum present and declared lawmakers would not reconvene until Sept. 4. That date is just 11 days before the top two U.S. officials in Iraq — Ambassador Ryan Crocker and military commander Gen. David Petraeus — must report to Congress on American progress in taming violence and organizing conditions for sectarian reconciliation.

The recess, coupled with al-Maliki's failure to get the key draft laws before legislators, may nourish growing opposition to the war among U.S. lawmakers, who could refuse to fund it.

Critics have questioned how Iraqi legislators could take a summer break while U.S. forces are fighting and dying to create conditions under which important laws could be passed in the service of ending sectarian political divisions and bloodshed. But in leaving parliament, many lawmakers blamed al-Maliki, saying he had failed to send them any legislation to consider.

"Even if we sit next month, there's no guarantee that important business will be done," said Mahmoud Othman, a prominent Kurdish legislator. The parliament already had extended its session by a month, having initially planned a recess for July and August.

Also Monday, a U.S. Marine was killed while conducting combat operations in the vast Anbar province west of Baghdad, the military said.

The attack raised to at least 75 the number of U.S. service members who have died in Iraq in July, the lowest number since November 2006, when at least 70 U.S. deaths were reported. The monthly toll topped 100 in April, May and June.

In all, at least 3,652 members of the U.S. military have died since the Iraq war started in March 2003, according to an Associated Press count. The figure includes seven military civilians.

The No. 2 commander in Iraq, Lt. Gen. Ray Odierno, expressed cautious optimism about the downturn last week. He said casualties had increased as U.S. forces expanded operations into militant strongholds as part of a five-month-old security crackdown aimed at clamping off violence in Baghdad, but were going down as Americans gained control of the areas.

"It's an initial positive sign, but I would argue we need a bit more time to make an assessment whether it's a true trend," he said.

In scattered violence reported by police Tuesday, at least 11 people were killed or found dead nationwide, including three Iraqi police in a drive-by shooting and one soldier in a roadside bombing. A teacher also was shot to death while driving to work in a mainly Sunni neighborhood in Baghdad.

Meanwhile, al-Maliki's government faced a threat by the main Sunni bloc in parliament to withdraw its Cabinet members if he doesn't meet a series of demands by Wednesday.

The Iraq Accordance Front, which has six Cabinet members and 44 of parliament's 275 seats, called for a pardon for security detainees not charged with specific crimes and the disbanding of militias, among other demands. But the government said the move amounted to blackmail and said the Sunni bloc had contributed in creating some of the very policies it now criticized.

A Sunni insurgent group jumped into the debate with an Internet statement posted Tuesday.

"We repeat our call to the Accordance Front to withdraw from the government and from the political process that gave those who elected it more killing, displacement and misery," the Islamic Army in Iraq said.

An unmanned U.S. drone also crashed late Monday while landing at an air base north of Baghdad, but it did not appear to be from hostile activity, the military said separately.