A U.S. military helicopter crashed north of the Iraqi capital Monday — the third American chopper to go down in 10 days — killing the two crew members. A resident said he saw the smoke trail of a missile before the aircraft plunged to the ground.

The military said the AH-64 Apache was conducting a combat air patrol when it went down in an area "known for terrorist activity."

Officials said it was too early to determine the cause of the crash, and the names of the soldiers were not released. Apaches hold only a pilot and a co-pilot.

Two extremist groups — the Salahudin al-Ayoubi Brigade and the Mujahedeen Army — claimed in separate Internet statements that they had shot down an American helicopter. The claims could not be independently confirmed.

A video purportedly released by the Mujahedeen Army was wobbly and showed what appeared to be helicopter in the far distance. The cameraman appeared to shoot the video over the shoulder of a militant with a shoulder-fired missile.

Monday's incident was the latest in a string of fatal U.S. military helicopter crashes in Iraq in recent weeks, fitting a wartime pattern of more frequent accidental and combat crashes during winter months. An OH-58 Kiowa observation helicopter went down near Mosul on Friday, killing the two pilots.

In Muqdadiya, about 55 miles north of Baghdad, Iraqi authorities said a car blew up next to a police convoy, killing six people.

Najim Abid, a medic at the city's main hospital, said five officers and a 6-year-old died from the blast and 16 civilians and three policemen were injured.

In other violence, gunmen in Baghdad killed a civilian and a policeman in separate incidents, police said. Gunmen also attacked a truck carrying goods for the U.S. military, killing the Iraqi driver, Sgt. Kamal al-Saeidi said.

Meanwhile, Iraq's electoral commission said Monday that it is throwing out votes from 227 ballot boxes in last month's parliamentary elections because of fraud, a tiny percentage of the total vote that shouldn't greatly affect overall results.

Complaints by Sunni Arab and secular Shiite Muslim parties charging voting fraud and other irregularities have delayed announcement of final results from the Dec. 15 election, slowing negotiations on forming a new, broad-based coalition government.

Election officials annulled some of the boxes because fake ballots were used, said Hussein Hendawi, an official with the Independent Electoral Commission of Iraq. The votes of about 53 boxes were annulled because too many votes were cast, he said.

Iraqis cast ballots at about 6,200 voting centers across the country Dec. 15, and there were an average of five ballot boxes at each. So 227 ballot boxes would be about two-thirds of 1 percent of the total vote, which was estimated at about 11 million ballots.

Hendawi said the commission studied 58 serious complaints, including 25 from Baghdad, which is Iraq's biggest election district with 59 seats in the 275-member parliament. A total of 1,985 complaints were lodged, but most were not considered serious.

Fewer irregularities occurred than in last year's vote for an interim parliament, Hendawi said.

The governing United Iraqi Alliance, a religious bloc based in the country's Shiite Muslim majority, held a strong lead in preliminary results announced earlier. But it didn't have enough seats to govern alone and will have to put together a coalition with Sunni Arab and Kurdish parties.

Although leading politicians have expressed hopes a government could be formed in February, most experts and officials agree it could take two to three months, as it did after the election last Jan. 30.

An international team assessing the fairness of the voting process said Sunday that it would release its final report Thursday. Iraq's election commission is expected to announce uncertified final results shortly after that, perhaps as soon as the weekend.

More complaints could be lodged after that, and it could take up to two weeks to study those complaints. Certified results would then be announced — likely sometime in early February — opening the way for negotiations in earnest over a coalition government.

On Sunday, the tribunal overseeing investigations of Saddam Hussein confirmed that the chief judge in a trial of the former leader and seven co-defendants had submitted his resignation.

It said Judge Rizgar Mohammed Amin wanted to quit for "personal reasons" and not because of government pressure, but his move would not prevent the resumption of the trial on Jan. 24 as scheduled.

Amin became fed up with criticism that he let the proceedings spin out of control, a court official said Saturday.

Saddam has often grabbed the spotlight during the nearly 3-month-old trial, railing at Amin, refusing to show up at one session, claiming he was tortured and openly praying in court when the judge would not allow a recess.

The former leader and his co-defendants are charged in the deaths of more than 140 Shiite Muslims from the town of Dujail who were killed in retaliation for a 1982 assassination attempt on Saddam. Conviction could bring a sentence of death by hanging.