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 military said a U.S. 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 blast tore through the stalls as the market was packed with afternoon shoppers buying vegetables and household goods in a predominantly Kurdish area in southern Kirkuk, 180 miles north of Baghdad.

Police initially said it was a homicide 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.

The blast shattered the glass facade and mirrors of Abdul Majeed Hamid's barber shop, wounding his 14 customers.

Hamid said he was in the middle of a heated debate with a customer about a U.S.-Iraqi security crackdown in Baghdad when the explosion struck.

"I was discussing with my customer the improving security situation in Baghdad and how this could have a positive effect on the situation in Kirkuk, but suddenly, a tremendous blast occurred and the shop was filled with smoke, screams and blood," he said.

Tensions have increased in Kirkuk 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. The area also has seen an increase in violence by militants believed to have fled the operations in the Baghdad area.

Elsewhere in northern Iraq, a suicide car bomber struck an Iraqi army patrol northeast of Mosul, killing four soldiers and wounding 14, army Col. Fahmi Soufi said.

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 Qaeda in Iraq linked insurgents.

In all, at least 45 people were killed or found dead nationwide.

The HH-60 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.

Hundreds of thousands of Shiite pilgrims, 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 eighth century saint, Imam Moussa al-Kadhim.

Baghdad authorities claimed success in preventing violence from marring Thursday's procession with a three-day driving ban that was to expire early Saturday and other measures. Only scattered violence was reported against the pilgrims.

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.

In another development, 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 that have increased because of insecurity and fighting.

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.