BAGHDAD - A car bomb struck a market in a Kurdish area in the northern city of Kirkuk on Friday, killing at least eight people and wounding dozens, police said. South of Baghdad, the U.S. military said a helicopter was forced down, leaving two soldiers injured.

The attack in Kirkuk, a disputed oil-rich city that has seen a recent rise in ethnic tensions, occurred while the capital remained relatively calm under a driving ban aimed at preventing such attacks during a major Shiite pilgrimage.

The helicopter was en route to support a planned mission when it made the forced landing in Youssifiyah, the military said, adding the cause was not immediately clear from initial ground reports but was being investigated. Two soldiers sustained non-life threatening injuries, according to the statement.

U.S.-led forces had secured the site and recovered the aircraft, military spokesman Lt. Col. Rudolph Burwell said.

An Iraqi army officer, who spoke on condition of anonymity because he wasn't authorized to release the information, said the helicopter went down after hitting an electricity pole at about 1:30 a.m. He said the raid was targeting a senior al-Qaida in Iraq leader in the agricultural area. Burwell said he could not confirm that report.

Youssifiyah, 10 miles south of Baghdad, is in the area south of Baghdad known as the triangle of death for the insurgent activity there.

It was the second helicopter to go down in less than two weeks. On July 31, an AH-64 Apache helicopter went down after coming under fire in eastern Baghdad. The two crew members were safely evacuated, the military said.

Insurgents also shot down a U.S. military helicopter south of Baghdad on July 3, and the two pilots were rescued with minor injuries, the military said.

Scattered violence struck Iraqis nationwide, with at least 15 people killed or found dead.

The deadliest attack was a parked car bomb that tore through the stalls as the market was packed with afternoon shoppers in a predominantly Kurdish area in southern Kirkuk, 180 miles north of Baghdad.

Police initially said it was a suicide attack, but police Brig. Gen. Sarhad Qader later said it was a parked car bomb. Qader said at least eight people were killed and 45 were wounded.

Tensions have increased as Kurds seek to incorporate the oil-rich city into their autonomous zone in northern Iraq -- a move opposed by Arabs and Turkomen in the area.

A roadside bomb also exploded near a minibus in Baqouba, 35 miles northeast of Baghdad, killing two passengers and wounding four others, while another civilian was killed in a drive-by shooting as he was walking elsewhere in the city, police said.

U.S. forces have claimed recent successes in calming the Diyala provincial capital after launching an operation to clear it of al-Qaida in Iraq linked insurgents.

Hundreds of thousands of Shiites, meanwhile, began the journey home a day after massing in the streets outside a golden-domed shrine in northern Baghdad to commemorate the anniversary of the death of an 8th century saint, Imam Moussa al-Kadhim.

A few shook their fists at U.S. soldiers standing alongside the procession route, but the march was mostly peaceful as authorities imposed a three-day driving ban that was to expire early Saturday.

The same festival was struck by tragedy two years ago, when an estimated 1,000 pilgrims were killed in a stampede over a bridge after panic that a suicide attacker was among them. And last year, snipers killed at least 20 people as the pilgrims walked through Sunni areas.

Iraqi Prime Minister Nouri al-Maliki was in Iran to talk about security and electricity deals. Iranian officials told al-Maliki that only a U.S. pullout would bring peace to his nation and claimed the Tehran government was doing its best to help stabilize neighboring Iraq.

Al-Maliki said decisions about an American pullout were between Baghdad and Washington. This issue "belongs to the Iraqis only and it is related to the readiness of the Iraqi armed forces and their ability to take over security responsibilities," he told The Associated Press during the visit.

Al-Maliki has long played a delicate balancing act in the bitter rivalry between his two allies, putting off Iranian calls for an American pullout while balking at U.S. pressure to take a tougher line against Tehran.

President Bush said he hoped al-Maliki's message to Tehran would be the same as the U.S. message -- that Iran should halt the export of sophisticated explosive devices used to attack U.S. troops in Iraq or "there will be consequences."

The United States and Britain sought to expand the U.N. mandate in Iraq with a draft resolution facing a Security Council vote on Friday.

The sponsors had delayed the vote so that Iraq's prime minister could revise the text, which would authorize the world body to help the government promote national reconciliation, better relations with its neighbors and deal with humanitarian concerns.

The newly revised text was circulated to the Security Council and Iraq's Foreign Minister Hoshyar Zebari sent a letter asking that the mandate of the U.N. mission, which expires Friday, be extended for a year -- a requirement before the resolution can be adopted.