Meanwhile

Over there:

BAGHDAD - The renegade cleric Muqtada al-Sadr urged Iraqi forces to stop cooperating with the United States and told his guerrilla fighters to concentrate their attacks on American troops rather than Iraqis, according to a statement issued Sunday.

The statement, stamped with al-Sadr's official seal, was distributed in the Shiite holy city of Najaf on Sunday — a day before a large demonstration there, called for by al-Sadr, to mark the fourth anniversary of the fall of Baghdad.

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"God has ordered you to be patient in front of your enemy, and unify your efforts against them — not against the sons of Iraq," the statement said, in an apparent reference to clashes between al-Sadr's Mahdi Army fighters and Iraqi troops in Diwaniyah, south of Baghdad. "You have to protect and build Iraq."

The U.S. military on Sunday announced the deaths of four American soldiers, killed a day earlier in an explosion near their vehicle in Diyala province northeast of Baghdad. The province has seen a spike in attacks on U.S. and Iraqi forces since the start of a plan two months ago to pacify the capital. Officials believe militants have streamed out of Baghdad to invigorate the insurgency in areas just outside the city.

Separately, a pickup truck loaded with artillery shells exploded Sunday near a hospital south of Baghdad, killing at least 15 people. The blast left a crater 10 yards wide, the Iraqi military said.