A mortar attack ignited a huge fire Monday night at an oil facility in northern Iraq, shutting the flow of crude oil to a major refinery, and a U.S. Air Force jet crashed in Anbar province, a hotbed of the Sunni-Arab insurgency, officials said. Al-Jazeera reported that the pilot was killed.

As Prime Minister Nouri al-Maliki prepared for a summit meeting with President Bush this week in Jordan, Britain said it expects to withdraw thousands of its 7,000 military personnel from Iraq by the end of next year, and Poland and Italy announced the impending withdrawal of their remaining troops.

Iraqi President Jalal Talabani arrived for an official visit in Iran, where he is expected to seek its help in preventing Iraq's sectarian violence from sliding into an all-out civil war. His departure was delayed by a three-day curfew, which the government lifted Monday.

Two mortar rounds hit the pipeline filtering facility 15 miles northwest of Kirkuk, according to an official at the North Oil Co., speaking on condition of anonymity because he was not authorized to speak to reporters.

The fire was burning out of control and could take hours or longer to extinguish, and the flow of oil from all of Kirkuk's rich fields has been shut down to the massive Beiji refinery to the southwest, the official said.

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After the F-16CG jet went down, a witness said other U.S. warplanes rushed to the crash site about 20 miles northwest of Baghdad and circled above it. The U.S. military, which released a statement on the crash, did not have any information on the suspected cause or the fate of the pilot.

But Al-Jazeera television showed videotape of the wreckage in a field and what appeared to be portions of a tangled parachute nearby, and the broadcaster said the video included scenes of the dead pilot but that they were too graphic to air.

One shot showed an Air Force seal that said Air Combat Command.

Mohammed Al-Obeidi, who lives in the nearby town of Karmah, said by telephone that he saw the jet flying erratically before it nose-dived and exploded in a field.

Separately, police and witnesses said U.S. soldiers shot and killed 11 civilians and wounded five on Sunday night in the Baghdad suburb of Husseiniya. The U.S. military said it had no record of any American military operation in the area.

"We were sitting inside our house when the Americans showed up and started firing at homes. They killed many people and burned some houses," said one of the witnesses, a man with bandages on his head who was being treated at Imam Ali Hospital in the Shiite slum of Sadr City. The police and witnesses spoke with Associated Press Television News on condition of anonymity to protect their own security.

On Monday, about 250 people attended a memorial service outside the hospital's morgue for the 11 victims, saying it was being conducted in the slum because the dead had been followers of the radical anti-American Shiite cleric Muqtada al-Sadr. The cleric and his Madhi Army militia are both based in Sadr City.

The U.S. command also said three of its soldiers were killed and two wounded in Baghdad on Sunday, the day that Iraq's government began to lift the curfew by allowing Iraqis to leave their homes on foot to shop at their local fruit and vegetable markets. The curfew was imposed Thursday after suspected Sunni-Arab insurgents used bombs and mortars to kill more than 200 people in Sadr City in the worst attack by militants in the war.

The U.S. wants Iran's mostly Shiite government to do more to help Iraq's Shiite-dominated government stem a surge in sectarian violence.

Talabani is a member of Iraq's Kurdish minority, but he had close ties with Iranian officials before Saddam Hussein was driven out by the U.S.-led invasion in 2003.

The Bush administration has accused Tehran of arming and providing logistical assistance to Shiite militias, and British Defense Secretary Des Browne said Monday that Iran's behavior in Iraq remains a deep concern.

"Support from within Iran goes to groups who are attacking our forces, but also to groups who are simply fueling the sectarian violence," Browne said in an address to the Royal Institute of International Affairs in London.

Hard-line Iranian President Mahmoud Ahmadinejad has said Iran is "ready to help" calm Iraq's fighting.

In other violence, gunmen opened fire on a crowded central Baghdad street on Monday morning, killing six Iraqis and wounding three, including some sitting in a parked car, said police Lt. Ali Muhsin.

Police in western Baghdad found the bodies of two Iraqis who had been kidnapped, blindfolded and shot, said police 1st Lt. Miathem Abdel-Razaq. Each week, the mutilated bodies of scores of Shiites and Sunnis are found across Iraq.

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