BAGHDAD — A series of rockets or mortar rounds struck Camp Victory, killing two members of the U.S.-led coalition and wounding 40 other people on the sprawling headquarters for U.S. forces in Iraq, the military said Thursday.

Most troops stationed at the base are American but there are small contingents from other countries.

The military said those wounded in Wednesday's attack included two "third-country nationals," meaning they were not Americans or Iraqis. More details on the attack were not immediately released.

U.S. bases in Iraq frequently face so-called "indirect fire," the military's term for a rocket or mortar attack, but Camp Victory is well-entrenched on the capital's western outskirts and such heavy casualties are rare.

On Sept. 11, one person was killed and 11 were wounded in a rocket attack on the complex, which includes lakeside palaces formerly used by Saddam Hussein that now house the headquarters of the Multi-National Forces in Iraq. The U.S. military said a 240 mm rocket provided to Shiite extremists by Iran was used in that attack.

By contrast, the U.S.-protected Green Zone, which houses the American and British embassies and the Iraqi government headquarters in central Baghdad, is far more vulnerable and has faced a series of deadly strikes in recent months.

U.S. commanders have said training and weapons provided by Tehran is helping militants to improve their aim.

In Thursday's violence, clashes between suspected al-Qaida gunmen and police at checkpoints near Baqouba killed at least one officer and wounded two others, according to a police official who asked for anonymity because he was not authorized to release the information.

The pre-dawn attacks lasted about three hours and occurred at two checkpoints in Abbara, north of Baqouba, which is about 35 miles northeast of Baghdad, according to police. One gunman was killed and several others fled, police said.

Just east of Baqouba, suspected al-Qaida gunmen took control of five Sunni villages, killing six people, including two police officers and wounding five others, a police official said. The attacks, which began Wednesday evening and continued until Thursday morning, happened two days after locals, supported by U.S. forces, had cleared the village of insurgents, the official said.

Elsewhere in Diyala province, gunmen killed five Iraqi civilians and wounded four in a morning attack on a minibus going from Khalis to Kirkuk, police said. Khalis is about 50 miles north of Baghdad. An ophthalmologist, the son of the local head of the Sunni Iraqi Islamic Party, also was shot to death in Mosul, about 225 miles northwest of Baghdad.

A suicide car bombing in a Kirkuk market killed seven and wounded 50. The target of the attack was a three-car police convoy carrying the traffic police chief and his guards, police said. Three of the policemen were among the dead and the chief was wounded.

The U.S. military released the names of three al-Qaida members killed in an airstrike Wednesday in western Baghdad. The three men — Abu Rami, Ammar Fadhil Kadhim and Fadil Salman, who is also known as Abu Ra'ad — were targeted for killing Abu Bilal, an imam who had been preaching against al-Qaida, the military said.

The insurgents planted four bombs in and around Bilal's house, one of which detonated. The men then entered Bilal's house, killing him and wounding his wife. Bilal's nephew killed two of the insurgents before the group fled, the military said.

U.S. troops pursued the militants as they assembled on a field west of Baghdad. The soldiers called in air support, which killed 13 members of the group, the military said.

Meanwhile, U.N. officials said they will be looking into whether war crimes and crimes against humanity were committed in recent shootings of Iraqi civilians by U.S.-hired contractors, and they urged U.S. authorities to hold private security firms accountable for unjustified killings of Iraqis.

"For us, it's a human rights issue," said Ivana Vuco, a human rights officer with the U.N. Assistance Mission to Iraq. "We will monitor the allegations of killings by security contractors and look into whether or not crimes against humanity and war crimes have been committed. "

Said Arikat, the U.N. mission spokesman, urged the U.S. government to hold those involved in indiscriminate gunning down of Iraqis "to the bar, to apply the rules of engagement and prosecute them."

On Wednesday, Iraqi officials demanded answers of an Australian-owned security company blamed in the killing of two Iraqi Christian women amid rising calls for a crackdown on private bodyguards used by the U.S. government.

The scrutiny of Unity Resources Group began a day after its guards allegedly gunned down the two women in their car, and less than a month after 17 Iraqis died in a hail of bullets fired by Blackwater USA contractors at a busy Baghdad intersection.

At a funeral in Baghdad's Armenian Orthodox Virgin Mary church on Wednesday, the Rev. Kivork Arshlian urged the government to punish those responsible. The immunity enjoyed by foreign security contractors in Iraq should be lifted, he said.

"This is a crime against humanity in general and against Iraqis in particular. Many other people were killed in a similar way," he said. "We call upon the government to put an end to these killings."

His comments reflected growing anger here against the contractors — nearly all based in the United States, Britain and other Western countries.

As the largest security firm operating in Iraq, much of that rage has been directed at Blackwater, which protects U.S. diplomats as they move about on Baghdad's dangerous streets. An Iraqi investigation into the Sept. 16 killings recommended that the State Department sever all contracts for the company's operations in Iraq within six months.

A top aide to Prime Minister Nouri al-Maliki told The Associated Press that Washington was considering meeting the demand, "but so far there has been no concrete answer from the U.S. Embassy showing it was definitely going to drop Blackwater."

The embassy declined to comment.

According to witnesses and police, the Armenian Christian women died when their white Oldsmobile was struck by bullets from two Unity guards as the convoy was returning to a company compound in the Karradah district. They said the woman driving the car appeared to be trying to stop when she was killed.

"We cannot say the guards shot at random, but we rather say that they used deadly force in a situation where they shouldn't have," said government spokesman Ali al-Dabbagh. "The preliminary investigation has shown that there was no threat to the convoy. The families of the victims will be summoned according to the legal procedures. They can file a law suit against the security company."

Unity Chief operating officer Michael Priddin said company officials were cooperating with Iraqi authorities in their investigations. He said the security team feared a suicide attack and fired only after issuing appropriate warnings for the vehicle to stop, including signs, strobe lights, hand signals and a signal flare.

Unity, which is owned by Australian partners but with headquarters in the United Arab Emirates, provides protection for USAID contractor RTI International. According to the USAID Web site, RTI has about $450 million in U.S. government contracts to work on local governance projects in Iraq. USAID is a semiautonomous arm of the State Department that manages American aide programs.

Associated Press writers Bushra Juhi and Hamid Ahmed contributed to this report.