Sunni Arab participation in a new government will not be enough to persuade Islamic extremists and Saddam Hussein loyalists to abandon the terrorist insurgency, the country's most powerful Shiite politician said Thursday.

Abdul Aziz al-Hakim, a cleric with close ties to Iran and head of Iraq's largest Shiite party, also said the Americans must address "mistakes" in the battle against Sunni-led terrorists and allow the Iraqis a bigger role in the fight.

The turbaned, soft-spoken cleric made his comments during an interview with The Associated Press in his heavily guarded residence along the Tigris River as the election commission was preparing to announce results of the Dec. 15 national ballot.

An alliance of Shiite religious parties, in which al-Hakim's group plays the leading role, is expected to claim the biggest number of seats in the new parliament but not enough to rule without Sunni and Kurdish partners.

Despite his calm demeanor, al-Hakim has a reputation for toughness honed by years as the commander of the Badr Brigade, a Shiite militia which fought Saddam's regime until it collapsed in the 2003 U.S.-led invasion.

That has given al-Hakim a fearsome reputation among Sunni Arabs, many of whom believe the Badr militia has infiltrated government security forces and are responsible for abuses against Sunnis. The Badr Brigade and al-Hakim's Supreme Council for the Islamic Revolution in Iraq deny the allegations.

During the interview, al-Hakim, who speaks only a little above a whisper, acknowledged the need to bring Sunni Arabs into the new government, which will be formed once the new parliament convenes.

U.S. officials hope the new leadership will win the trust of the Sunnis and defuse the insurgency so that American and other international troops can begin to go home.

"We are convinced of the necessity that the Sunnis should participate along with us in the government because they are an important component in Iraq," he said. "As for who is going to join the government with us, this matter is related to who is closer to us regarding the principles we believe in."

But al-Hakim added: "The important thing is that (Sunnis) believe that there is a new reality in Iraq. The important thing that is they believe in the necessity of the participation and shouldering responsibility in the (parliament) and government."

"Every day we are getting closer to accepting this reality. But there are some groups that will not accept this," al-Hakim said, citing religious extremists and Saddam loyalists. "Those people will continue confronting the government. ... Those people should be confronted firmly by the government."

To do that, al-Hakim said the Iraqis and their coalition partners must agree on a greater counterinsurgency role for Iraqi forces and "allow the Interior and Defense ministries to operate and to allow the leaderships in those two ministries to make decisions and move to achieve their goals."

The Interior Ministry, currently controlled by al-Hakim's party, has been particularly criticized by Sunnis for alleged abuses.

Sunni Arabs, believed to account for about 20 percent of Iraq's 27 million people, dominated political life for generations, and many of them resent the rise to power of the Shiite majority, which suffered under Saddam's regime.

Many Sunnis refuse to accept the widespread belief that Shiites now number about 60 percent of the population. The decision by many Sunnis to boycott the January 2005 election enabled Shiites and Kurds to dominate the outgoing parliament, sharpening sectarian tensions and fueling the insurgency.

Sunnis participated in far greater numbers in last month's election and are expected to gain more seats in the new legislature.

One of parliament's first tasks will be to consider amendments to the new constitution, a demand of Sunni politicians who opposed several major provisions of the charter. If the new parliament approves amendments, they will be presented to the voters in a referendum.

However, al-Hakim made clear that the Shiites will oppose major concessions on some key Sunni demands. Many Sunnis oppose provisions transforming Iraq into a federal state and banning key members of Saddam's Baath party from government jobs.

"There is a group of principles, first to maintain the soul of the constitution, second is the federalism issue, third is a clear stand on terrorism, fourth a clear stand on the Baath and Saddamists as it is mentioned in the constitution and fifth the issue of civil liberties," al-Hakim said.

Many Sunnis fear that federalism will lead to the breakup of the country and open the door to Iranian influence in a future, Shiite-dominated region in the south. Sunnis also fear that a widespread purge of former Baath party members would curb the rights of the Sunni community, which dominated Baathist ranks.