Iraq's most influential Shiite Muslim cleric warned of "grave problems" if nothing is done to stem the proliferation of firearms in the country and blamed clashes between his supporters and followers of a radical cleric on the weakness of Iraq's U.S.-backed authorities.

In written comments given Sunday to The Associated Press, Grand Ayatollah Ali Hussein al-Sistani (search), spiritual leader of most of Iraq's Shiite majority, also said there could be "no substitute" for a general election to choose delegates to a convention to draft a new constitution despite U.S. demands for a quicker selection process.

The U.S.-led coalition has repeatedly stated its preference for a faster method to choose the delegates — such as having the U.S.-appointed Iraqi Governing Council (search) select from a list of legal experts put forward by tribal and other leaders. Coalition officials believe choosing them by general election would take too long.

A U.N. Security Council resolution adopted unanimously this month sets a Dec. 15 deadline for the Governing Council to come up with a timeline for adopting a constitution and holding national elections.

However, the Governing Council has been unable to agree on a formula for choosing delegates to the constitutional convention. Preparations for an election to choose delegates could take six to 12 months, but some council members say the drafting of the constitution could begin while these preparations were under way.

Al-Sistani's comments were made in reply to written questions submitted by AP to his office in the holy city of Najaf. His replies, also in writing, bore his office's seal, meaning they were considered official statements.

His views are considered significant because of the enormous prestige he commands among Iraq's Shiites, who comprise more than 60 percent of the country's 25 million people.

Al-Sistani's demand for measures against illegal arms possession appeared to be a call on U.S. and Iraqi authorities to take action against the Imam al-Mahdi Army, a militia set up by firebrand cleric Muqtada al-Sadr (search), whose members fought nightlong battles against al-Sistani's supporters a week ago in the holy Shiite city of Karbala.

Al-Sadr, a populist cleric whose militant message appeals to poor and young Shiites but who lacks al-Sistani's scholarly weight, has been flaunting his army recently, allowing recruits to parade with their firearms in Najaf and Karbala as well as in a Shiite-dominated Baghdad district.

Members of the Imam army are thought to be responsible for the deaths of two U.S. soldiers in an ambush in Baghdad on Oct. 9. Pentagon officials have since spoken about al-Sadr as a "threat" to the U.S.-led occupation authorities and of preparations to take action against him.

Al-Sistani, however, appeared to place the blame on the coalition and U.S.-backed Iraqi authorities.

"What happened in holy Karbala ... was the result of the absence of an effective and powerful central authority and the existence of a large number of weapons in the hands of unruly individuals.

"There may be new grave problems if measures are not taken," he said.

The Iranian-born al-Sistani did not mention al-Sadr by name and denied any involvement in last week's fighting, which left up to 10 people dead and scores injured in Karbala. Al-Sistani, who refused to meet with al-Sadr after the clashes, said the violence pitted "some residents against armed groups."

Al-Sistani, like other moderate Shiite leaders in Iraq, has been reluctant to openly criticize al-Sadr for fear of exacerbating divisions among Shiites at a time when he believes the long-oppressed community should show unity as it moves close to taking its place as the country's single most dominant bloc.

"Differences in views and the existence of various ideologies within the Shiite community is natural and should not worry anyone," said al-Sistani. "A quiet dialogue between concerned parties is the ideal way to resolve differences."

Elaborating on an earlier edict, al-Sistani said there was not one party or authority in Iraq that can select delegates to a constitutional conference in a way that would ensure fair representation of all segments of society.

"Furthermore, it is certain that personal, party, religious and ethnic interests will interfere one way or another in the selection process, rendering the conference illegitimate," he said.

"There is no substitute for a general election to choose members of a constitutional conference."

A new constitution that enshrines the rights of all Iraqis after more than three decades of tyrannical, one-party rule will be the cornerstone of the free and democratic nation that L. Paul Bremer, America's top official in Iraq, envisages for the nation. Bremer wants a new constitution adopted in a referendum that will be followed by a general election and a representative government.