A suicide truck bomb ripped through the Interior Ministry headquarters in the relatively peaceful Kurdish city of Irbil on Wednesday morning, killing at least 14 people and wounding dozens, officials said.

Kurdish officials blamed Al Qaeda linked insurgents for the devastating bombing -- the first major attack to hit the regional capital in more than three years.

The bombing came as Vice President Dick Cheney arrived in Baghdad for an unannounced visit that was to include meetings with top Iraqi government officials, leaders of influential Iraqi factions and the senior U.S. military commander here.

The U.S. military announced Wednesday that an American soldier was killed and four others were wounded the day before in a shooting attack in the volatile province of Diyala, northeast of Baghdad.

The explosion in Irbil, 215 miles north of Baghdad, underscored how even relatively safe areas of the country were not immune from the violence.

Irbil, the capital of Iraq's autonomous Kurdistan region, had been spared much of the sectarian violence wracking the rest of Iraq.

But attacks have been on the rise in southern and northern areas in Iraq as Sunni and Shiite militants have fled a three-month-old security crackdown in Baghdad and brought their brutal tactics with them.

The Interior Ministry building was badly damaged. Kurdish television showed piles of rubble and twisted metal beams. Rescue workers reached into the wreckage to pull out one of the victims of the blast. Windows were blown out down the street and wreckage was scattered nearly 100 yards away.

The nearby security headquarters was also damaged.

Zariyan Othman, the Kurdish health minister, initially said 19 people were killed. But the regional minister for the interior, Karim Sinjari, later said 14 were killed and 87 wounded. Officials blamed the discrepancy on the doublecounting of some bodies.

Kurdish lawmaker Mahmoud Othman blamed the attack on Ansar al-Sunnah, a Sunni Arab insurgent group, and Ansar al-Islam, a mostly Kurdish militant group with ties to Al Qaeda in Iraq. Ansar al-Islam has been blamed for a number of attacks, including attempts to assassinate Kurdish officials.

Othman said authorities learned that insurgents were planning a large attack a week ago when police arrested a militant cell in the town of Sulaimaniyah.

"During questioning they confessed that were getting training lessons in a neighboring country and that was Iran," he said.

The last major attack in Irbil took place Feb. 1, 2004, when twin suicide bombers killed 109 people in two Kurdish party offices. Ansar al-Sunnah claimed responsibility for that attack.

"Kurdistan is a safe region and this will have its effect on trade, and companies will fear coming to this region," Othman said.

Elsewhere in northern Iraq, gunmen killed two members of the minority Yazidi religious sect and wounded another in a drive-by shooting in Mosul.

A car bomb also exploded near an Iraqi military checkpoint in Baghdad, killing one civilian and wounding two soldiers, police said.

Police found four decapitated heads in the Sabtiyah area north of Baqouba, 35 miles northeast of Baghdad, health officials said. The body of a security officer was also found shot in the head and chest in Diwaniyah, 80 miles south of Baghdad, police said.

The attacks came a day after a homicide car bomber struck a crowded market in the Shiite holy city of Kufa, killing at least 16 people and threatening to further stoke sectarian tensions in relatively peaceful areas south of Baghdad.

U.S. officials have expressed fears that Sunni insurgents led by Al Qaeda are carefully picking their targets to provoke retaliatory violence to derail efforts to stabilize the country.

The predominantly Shiite southern areas also have seen a spike in violence and unrest, blamed in part on militants who have fled a security crackdown in Baghdad. The U.S.-led offensive is intended to curb violence and allow the Shiite-led government some breathing room to implement reforms, including proposals to empower minority Sunnis Arabs and help end the insurgency. There has been little evidence, though, of any movement toward those reforms.

The U.S. military, meanwhile, said two children were among five people killed when a helicopter fired at militants operating an illegal checkpoint and planting a roadside bomb near Mandali, a town on the Iranian border 60 miles east of Baghdad.

Two suspected militants -- identified as Abd al-Qader Dadoush and Wadeh Kalifa Doudoush -- also were killed, according to a statement.

The military said the cause of the civilian casualties was under investigation. But it denied reports that a U.S. helicopter had fired on an elementary school, killing seven students in Baqouba, the provincial capital of Diyala that lies to the west of Mandali.