STEVE INSKEEP, host:

This is MORNING EDITION from NPR News. I'm Steve Inskeep.

RENEE MONTAGNE, host:

And I'm Renee Montagne.

Iraqi Shiite cleric Moqtada al-Sadr today called for calm after a night of violent clashes between his supporters and a rival militia in Baghdad in several southern cities. This rift within Iraq's Shia has erupted at an acutely sensitive time. Iraq's politicians are supposed to agree on a draft constitution by midnight tonight. It's still unclear whether they'll do so. The deadline has been extended twice already. We're joined from Baghdad by NPR's Philip Reeves.

And, Philip, information about the fighting between these two Shiite groups is still coming in. What is the latest at this moment?

PHILIP REEVES reporting:

There have been reports of violence in several Shiite cities in the south and also Baghdad today. Now this is a conflict between Moqtada al-Sadr's militia, the Mahdi army, and the Badr Brigades. That's a militia linked to the Shiite political party SCIRI, the Supreme Council for the Islamic Revolution in Iraq. You'll recall hundreds of lives were lost last year, some of them American, when Sadr's Mahdi army rose up twice. Now we've been told that in Basra, the TV station run by the Badr Brigades was attacked at dawn today with rocket-propelled grenades and burnt down.

There's a report that mortars were fired at a SCIRI office in Amarah, which is southwest of Baghdad. And in Baghdad's Sadr City--that's the slum whose several million poor Shiite population form the core of Sadr support--it's tense today. Hundreds of young men have been seen on the streets. There are sporadic gun shots. Yesterday, the Mahdi army attacked three Badr offices in Baghdad, and this morning they burnt down another one.

MONTAGNE: And how did this start?

REEVES: It began in Najaf at the recently re-opened office of Sadr, which is in the middle of the city near the famous Shiite shrine of Imam Ali. Details are unclear and they're disputed. There appears to have been a demonstration by people opposed to Sadr who wanted the office shut down. The Mahdi army refused to leave. Sadr people say this demonstration was an attack on their office and that the Badr Brigades were behind it. The police got involved. And there are allegations the crowd was fired on. Six people in the end were killed and dozens injured. And when the news of that spread, it went through to Baghdad. And within a few hours, there were attacks there on SCIRI and Badr officers.

These rival Shiite groups, by the way, have been vying for influence for months. There have been--tensions between them have cranked up recently with large demonstrations organized by Sadr to protest against the constitution and, in particularly, the creation of a federal Iraq. SCIRI supports the constitution and its leader also raised the temperature earlier this month by calling for the Shiite south to be made into a large federal entity.

MONTAGNE: And what kind of reaction has there been to all this?

REEVES: Well, I think it's a reflection on how unstable and tense the situation is, that the prime minister, Ibrahim Al-Jafari, appeared on television with an appeal last night for calm. And today in Najaf, Sadr also appeared on TV, also appealing for calm. He said that though he wouldn't forget the attack on his office, Iraq's passing through a difficult period that requires unity. He also, however, demanded that his chief rival, the head of SCIRI, Abdel-Aziz al-Hakim, condemn the attack on Sadr's Najaf office.

MONTAGNE: And just back to the question of the hour, if you will, what's the likelihood that the constitution will go through the National Assembly today, fulfilling the deadline?

REEVES: Well, I hesitate to make any prediction, as twice in the last 10 days they have, at the last minute, granted themselves extra time, extending the deadline. There's still no sign, though, that the Sunni Arabs have dropped their objections. And, in fact, today, several Sunni Arab negotiators have been reiterating those objections. There are, however, some who expect the Shiite, who control the parliament--they have the largest number of seats in parliament--will try to force the constitution through and will successfully do so because of their majority.

INSKEEP: That's NPR's Philip Reeves speaking with NPR's Renee Montagne. Transcript provided by NPR, Copyright NPR.

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