STEVE INSKEEP, host:

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

LINDA WERTHEIMER, host:

And I'm Linda Wertheimer. Renee Montagne is on vacation.

Iraq's leaders have less than a week to approve a new constitution, but there's little sign yet of agreement on a draft document which the National Assembly must approve by Monday. The constitution then goes to the voters for a referendum in the fall that in turn leads to elections in December. Meanwhile, there's no sign of any decrease in daily violence. Today brought news of four more American soldiers killed while on patrol yesterday. NPR's Philip Reeves is in Baghdad.

Philip Reeves, how did these latest US deaths occur?

PHILIP REEVES reporting:

Well, what we know so far is that they happened in Baiji, which is north of Tikrit. This is a Sunni town and one of the areas where the Sunni insurgency has been at its most violent. Four soldiers were killed and six injured. They were attacked late last night whilst on patrol. One report, quoting the police, says that, "at the scene there are two burned-out humvees and one large armored vehicle also wrecked." Well, the US military says that it was caused by an improvised explosive device. Now this, of course, is a roadside bomb in any other language. This will underscore concerns about the toll being taken by these devices. The military says that these bombs are becoming more sophisticated and therefore potentially more deadly. US and British officials have been alleging that they're being built in Iran and smuggled into Iraq.

WERTHEIMER: Well, from this side, US casualties do seem to be on the rise. Is that right?

REEVES: Certainly, August is so far proving a very costly month for the US military. We're one-third of the way through and 43 military personnel have been killed. By contrast, in all of July, the death toll among Americans was 54, although it must be said that June and May were somewhat higher, about 80. Of course, the figure for this month includes 14 Marines whose vehicle was blown up by a roadside bomb in Hadithah and six other Marines who were killed by small arms fire two days before that. It should also be said that Iraqis are taking a terrible toll. Not a day passes at the moment without bodies turning up, victims apparently of sectarian bloodletting and score settling. Today, three more were found in Baghdad on the edge of Sadr City, which is the huge Shiite neighborhood in Baghdad. And they had been shot and were found, as is usually the case with these corpses, with their hands tied behind their backs.

WERTHEIMER: What about talks on the constitution, Philip? Is there any sign of progress there?

REEVES: No. They continued yesterday after being set back for a day by a sandstorm which hit Baghdad. They're tackling one of the toughest issues now which is whether Iraq should have a federal structure. This is a core demand of the Kurds in northern Iraq who want their autonomy to be enshrined in the constitution. A senior Kurd in the Iraqi press this morning is saying that that demand is non-negotiable, so these talks are going to be hard going. There's resistance to the Kurdish demands amongst Sunni Arabs in particular who fear the breakup of Iraq and the loss of substantial oil revenues. Now they want the issue to be postponed till there's a new parliament which they hope will have more Sunni Arabs in it after elections, which are scheduled for December.

WERTHEIMER: NPR's Philip Reeves reporting from Baghdad. Thanks.

REEVES: You're welcome. Transcript provided by NPR, Copyright NPR.