In Iraq, cleric Muqtada Sadr threatens war

The warning was the closest the cleric has come to canceling the truce he called in August, and it coincided with an Iranian denunciation of U.S. airstrikes in support of the Shiite-led government's military offensive.

The United States accuses Iran of providing training, arms and other aid to Shiite extremists. The Iranian ambassador's comments, coming on the same day as Sadr's threat, were expected to fuel the U.S. allegations and exacerbate the explosive situation.

The statement, which Sadr said was his "last warning," made it clear that, nearly a month into the offensive against Shiite militiamen, the fighting is far from over. It also underscored the deepening rift between Sadr and Iraqi Prime Minister Nouri Maliki, exposing yet another political rivalry, this one among Shiites, that will hamper national reconciliation efforts.

If Sadr makes good on his threat, it would be the third time his forces have risen up against U.S. forces, and it would be a setback to Gen. David H. Petraeus' efforts to maintain security gains made since the deployment last year of 28,500 additional American troops.

The last of those forces is scheduled to leave Iraq in July, and U.S. military leaders had banked on Sadr's truce to keep Shiite extremists pacified while soldiers focused on quelling Sunni militants linked to Al Qaeda in Iraq. Several recent bombings characteristic of Al Qaeda in Iraq have indicated that Sunni militants are regrouping in areas that had been relatively quiet.

If Sadr were to call his militia back to action, the United States could find itself in the same situation it was early last year, when the high level of violence prompted President Bush to boost troop levels.

At least 12 people were reported killed Saturday in the latest battles in Sadr's Baghdad power base, Sadr City. In Basra, 250 miles to the south, witnesses and military officials reported gun battles in Hayaniya, a western neighborhood that had been held by the Mahdi Army.

A police official in Basra said Iraqi forces had seized control of Hayaniya and had detained scores of gunmen and confiscated weapons and ammunition. There was no independent confirmation of the statement.