Insurgents Kill at Least 18 Iraqis

Insurgents launched a new salvo of attacks five days ahead of a crucial constitutional referendum, killing at least 18 Iraqis and a U.S. soldier Monday with homicide car bombs, roadside explosives and drive-by shootings, police said.

Five mortar shells were fired at a hotel in the southern city of Hillah (search) where a U.S. regional embassy office is based, with one round hitting the building and leaving a large hole in a wall, police said. No casualties were reported.

Gunmen also opened fire on a convoy of cars carrying members of an Arab League (search) delegation that is visiting Iraq, but no one was hurt, police said.

The attacks came as Shiite and Kurdish officials continued to negotiate with Sunni Arab leaders over last-minute additions to the constitution, trying to win Sunni support ahead of Saturday's referendum. U.S. officials were acting as mediators.

But the sides appeared to remain far apart over basic issues — including the federalism that Shiites and Kurds insist on — and copies of the draft constitution already are being distributed to the public across the country.

U.S. and Iraqi officials see the referendum as an important step in the country's democratic reforms and the eventual withdrawal of U.S.-led coalition forces.

But many minority Sunnis plan to vote "no," fearing the document would create two oil-rich and nearly autonomous regions — a Kurdish one in the north and a Shiite one in the south — and leave most Sunnis isolated in central and western Iraq.

That was clear in the northern city of Mosul (search) on Monday when about 600 Sunni politicians, tribal leaders and clerics met and urged Iraqis to reject the constitution, saying it would partition the country along secular lines. "Our rejection of the constitution is motivated by our desire for a united Iraq, not because we are Sunnis," they said in a statement.

Sunni-led insurgent groups have demanded a boycott in the vote and were launching attacks across the country, killing hundreds of Iraqis in the last two weeks.

Sunnis can defeat the charter if they get a two-thirds "no" vote in any three of Iraq's 18 provinces — and they have the potential to make that threshold in four provinces. But turnout is key, since they must outweigh Shiite and Kurdish populations in some of those areas.

On Sunday, militants killed 13 Iraqis, including a Shiite teacher who was dragged out of his classroom and shot to death at a college in the town of Samarra, north of Baghdad.

In the last 15 days, at least 338 people have been killed across Iraq, including nine American soldiers who died in a series of offensives the U.S. military has been waging in western Iraq to try to knock Al Qaeda (search) militants and other insurgents off balance and prevent attacks during the referendum on the constitution.

In Monday's worst attack, a homicide car bomb exploded near a U.S.-Iraqi checkpoint leading into the highly fortified Green Zone, where Iraq's parliament and the U.S. Embassy are located. The blast killed a U.S. soldier, three Iraqi policemen and three civilians, U.S. and Iraqi officials said.

Teacher Riyadh Qassim heard the blast from his nearby elementary school.

"A car bomb exploded. We ran out of school and saw two cars engulfed in flames, one of them a police car. Some of the policemen were in a panic," he said in an interview with Associated Press Television News.

The American death brought to 1,954 the number of U.S. service members who have died since the beginning of the war in 2003, according to an Associated Press count.

At least two other suicide attackers detonated car bombs within an hour of the lethal attack, wounding four Iraqi policemen, police said. At about the same time, a homicide car bomb went off in Khaldiyah, about 75 miles west of Baghdad, but there were no immediate reports of casualties.

Four policemen were also killed in shootings in Baghdad.

In Kirkuk, a city 180 miles north of the capital, four Iraqi soldiers were killed in two separate roadside bomb attacks, police said. Farther to the north, two Sunni Arab political leaders, an Iraqi soldier and an Iraqi policeman died in separate drive-by shootings in Mosul, officials said.

In the attack on the 10-member Arab League delegation, gunmen in four vehicles pulled alongside the diplomats' cars on a highway in Baghdad and started shooting, said police Maj. Mousa Abdul-Karem. The convoy was driving toward a western neighborhood of Baghdad for a meeting with the Muslim Scholars Association, an Arab Sunni Muslim group.

The delegation arrived last weekend to lay the groundwork for an Iraqi "reconciliation conference" it hopes to hold after the referendum. It was the first time the pan-Arab organization has tried to take a direct role in Iraq since the 2003 U.S.-led invasion.

It was not immediately clear who launched the attack.

In cities, towns and villages across Iraq, 5 million copies of the official text of the constitution were being distributed to voters to consider before the polls.

But all sides were still debating last-minute changes in a bid to swing some Sunnis to a "yes" vote. Kurdish leader Massoud Barzani (search) continued to meet Monday with Sunni Arab leaders to try to convince them about the changes, officials from all sides said.

U.S. Ambassador Zalmay Khalilzad (search) "has a central role in the talks," said Kurdish legislator Mahmoud Othman, but he would not say if the envoy was actually attending the meetings. U.S. officials could not be reached for comment, but have confirmed in recent weeks that Khalilzad was involved in discussions over last-minute "tweaks" to the charter.

When Iraqi negotiators completed the draft constitution late last month, Sunni Arabs refused to endorse it. Some complained the negotiating process had been rushed under pressure from Washington to stick to the tight timetable that had been set for Iraq's political process.