BAGHDAD, Iraq - A radical Shiite cleric called on his followers today to end clashes with Shiite rivals so that stalled talks on a new constitution can proceed. Fighting continued for a second day after the cleric's office in Najaf was burned and four of his supporters were killed.

Following the appeal by cleric Muqtada al-Sadr, leaders of the country's political factions met to try to reach an agreement on the draft constitution. Today was the final day of a 72-hour extension granted Monday night by parliament after Sunni Arabs blocked a vote on the charter, which was accepted by Shiite and Kurdish negotiators.

After meeting with 15 Sunni members of the constitution drafting committee, Iraq's President Jalal Talabani said consensus on the new constitution could be reached soon.

It was unclear whether parliament would meet today to vote on the draft. Mahmoud Othman, a Kurdish member of the drafting committee, said lawmakers were supposed to meet later to ratify it.

But Shiite representative Khaled al-Attiyah said there was no need to vote because "the job was done" when the draft was handed to parliament on Monday. Another Shiite, Nadim al-Jabiri, said there would be no vote today because the draft will be approved or rejected in a popular referendum on Oct. 15.

In calling for calm, al-Sadr urged "all believers to spare the blood of the Muslims and to return to their homes,"

"I will not forget this attack on the office ... but Iraq is passing through a critical and difficult period that requires unity," he told reporters in his home in Najaf.

He demanded that Abdul-Aziz al-Hakim, leader of the rival Supreme Council for the Islamic Revolution in Iraq, or SCIRI, to condemn "what his followers have done." SCIRI has denied any role in the attack on al-Sadr's office.

"I urge the believers not to attack innocent civilians and not to fall for American plots that aim to divide us," al-Sadr said. "We are passing through a critical period and a political process."

The crisis erupted Wednesday when al-Sadr's supporters tried to reopen his office across the street from the Imam Ali mosque in Najaf, the most sacred Shiite shrine in Iraq. Rivals tried to stop the move, fights broke out and the office was set afire.

Armed attacks against offices of al-Sadr's movement and SCIRI then spread across the Shiite heartland of central and southern Iraq. Twenty-one pro al-Sadr members of parliament and three top government officials announced they were stopping official duties in protest of the Najaf attack.

Legislator Bahaa al-Araji said today the suspension will continue "until the leader's demands are met and until the investigation is over."

Before al-Sadr spoke, the violence continued today.

Al-Sadr supporters in Diwaniyah, 105 miles south of Baghdad, occupied parts of the city, setting up checkpoints and firing on police and rival groups, police Capt. Hussein Hakim said.

Some residents fled to nearby villages, he said.

SCIRI members torched a building belonging to al-Sadr's movement in the Baghdad suburb of Nahrawan, said police Lt. Ayad Othman. In retaliation, al-Sadr's followers set fire to an office of SCIRI's Badr Brigade militia in Baghdad's heavily Shiite neighborhood of Sadr City.

Clashes also broke out in Amarah, where al-Sadr's militiamen attacked the headquarters of the Badr group with mortars. Five attackers were killed, al-Sadr officials claimed.