Iraq's (search) interim prime minister declared on Wednesday that the success of the national elections had dealt a major blow to the insurgents. But in a clear sign militants plan to continue their attacks, 12 Iraqi soldiers were killed in an ambush in northern Iraq.

The Iraqi troops were returning to the northern city of Kirkuk, where they guard oil facilities, when armed men ambushed them Wednesday near the village of Zab, Maj. Gen. Anwar Mohammed Amin (search) said Thursday.

The ambush was the deadliest attack since Sunday's general elections. A U.S. Marine and two Iraqis who work on a U.S. military base were also killed in separate attacks.

In another sign of potential trouble, a major Sunni clerical group declared that Sunday's elections "lack legitimacy" because many Sunni Arabs did not participate, saying the new government would have no mandate to guide the nation's future.

That suggested problems remain in reconciling with the Sunni Arabs, who comprise about 20 percent of Iraq's 26 million people but form the core of the insurgency.

Nevertheless, both Prime Minister Ayad Allawi (search) and his major Shiite Muslim rivals reached out to the Sunnis, promising them a major role in drafting the new constitution even though many shunned the ballot — either out of fear of rebel attack or opposition to the electoral process.

"Definitely the Sunni Muslims will take part in the government and will have a role in the drafting of constitution," Abdul-Aziz al-Hakim, head of the main Shiite political faction, told The Associated Press.

Allawi, a secular Shiite backed by the Americans, told Iraqi television that the elections, which drew large turnouts except in Sunni insurgent strongholds, constituted a "major blow to all forces of terrorism."

He noted that attacks by Sunni insurgents had fallen dramatically since the elections but it was unclear whether the drop was the start of a trend. Insurgent activity also slowed after the transfer of sovereignty to the Iraqis in June but picked up weeks later. Allawi spoke before the 12 Iraqi security forces were killed.

"They might be reorganizing themselves and changing their plans," Allawi said of the insurgents. "The coming days and weeks will show whether this trend will continue ... But the final outcome will be failure. They will continue for months but this (insurgency) will end."

Following the election, U.S. military planners hope to shift from offensive operations against the insurgents to training Iraqi forces to do the job. Still, U.S. troops are continuing offensive operations, arresting four suspected rebels in northern Iraq and killing a suspected member of an al-Qaida-linked group northwest of Baghdad, the U.S. command said Wednesday.

Three days after the balloting, the Iraqi election commission has still not released any results or turnout figures, promising them with a week. Political sources say the ticket endorsed by the Shiite clergy was expected to win the largest share of the 275 National Assembly seats. Tickets led by Kurdish politicians and by Allawi also were running strong.

Al-Hakim, the head of the Shiite ticket, suggested Wednesday that his group would insist on the prime minister's post, saying his faction had several qualified candidates. That could mean Allawi might lose his job in the new administration if the Shiite ticket ends up with more than half the Assembly seats.

Still, the new government's ability to reconcile with disaffected elements in the Sunni community is considered the key to stability and to enabling the 170,000 mostly American foreign troops to leave.

The U.S. military on Thursday said a member of the 1st Marine Expeditionary Force was killed in combat in the western Anbar province on Wednesday. At least 1,436 American service members have been killed in Iraq since the March 2003 invasion.

Also Thursday, gunmen opened fire on a car carrying Iraqis who work on a U.S. military base in Baqouba, north of Baghdad, killing two passengers, police and hospital officials said.

In its first official statement since the ballot, the Sunni clerical Association of Muslim Scholars, which had called for an election boycott, said the new government would lack legitimacy because many Sunnis stayed home on election day.

The association said the new government would lack the mandate to draft a new constitution — one of the major duties of the new National Assembly.

"We cannot participate in the drafting of a constitution written under military occupation," said association spokesman, Mohammed Bashar al-Feidhi.

Despite statements by Sunni hard-liners, Allawi met with leaders of the 16 major political factions to discuss plans for the new government. The group included two of the leading Sunni politicians — President Ghazi al-Yawer and elder statesman Adnan Pachachi — and Finance Minister Adel Abdul Mahdi, a Shiite mentioned as a possible prime minister.

Allawi said he would meet Thursday with representatives of groups that did not take part in the elections but names of the participants were not released.

Iraqi politicians were relieved that the elections went off without major violence, despite rebel threats to "wash the streets in blood." More than 40 people were killed in eight suicide bombings and about 100 attacks on polling stations, but the level of violence was not extraordinary for a people hardened by years of war, repression and terrorism.

U.S. and Iraqi officials attributed the success to a massive security operation, which included tens of thousands of soldiers and police on the streets, a ban on most private vehicles, closing the borders and extended curfew hours. Those measures have since been relaxed.

Encouraged by the election success, the police chief in the city of Mosul, Gen. Mohammed Ahmed al-Jubouri, gave insurgents two weeks to hand in their weapons or he would "wipe out any village" that gave them shelter.

Mosul has been tense since insurgents rose up in November in support of militants under siege in Fallujah, west of Baghdad. The entire 5,000-member police force deserted before U.S. and Iraqi troops regained control.

Despite the lull in major attacks, insurgents blew up an oil pipeline Wednesday near the central city of Samarra, police said. The pipeline serves domestic power stations in Baghdad and Beiji and does not affect exports.

Four civilians were killed Wednesday in a drive-by shooting in Iskandariyah south of Baghdad, police said. The motive was unclear.