Iraq's Sadr calls million-strong march against U.S.

By Peter Graff and Ahmed Rasheed

BAGHDAD (Reuters) - Shi'ite cleric Moqtada al-Sadr called on Thursday for a million Iraqis to march against U.S. "occupiers", threatening a massive show of strength a week after his Mehdi Army militia battled U.S. and government troops.

The government said it would not try to block the April 9 march if it was peaceful, though Prime Minister Nuri al-Maliki, who ordered a crackdown on militia in the southern city of Basra last week, threatened more strikes against Sadr's strongholds.

A statement released by Sadr's office in the holy city of Najaf called on Iraqis of all sects to descend on the southern city, site of annual Shi'ite pilgrimages that attract hundreds of thousands of worshippers.

"The time has come to express your rejections and raise your voices loud against the unjust occupier and enemy of nations and humanity, and against the horrible massacres committed by the occupier against our honourable people," it said.

The demonstration, called for the fifth anniversary of the fall of Baghdad on Wednesday, raises the prospect of unrest coinciding with a politically sensitive progress report to Congress by the top U.S. officials in Iraq.

"If his intention is to get a whole lot of people together and go and make trouble in Najaf, I don't think that is going to be very popular," U.S. ambassador Ryan Crocker told a briefing.

U.S. forces called in helicopter strikes during a clash with suspected Sadr gunmen on Thursday in the city of Hilla and bombed a house in Basra overnight, after days of relative calm that followed a truce Sadr announced on Sunday.

The truce ended six days of fighting that spread through southern Iraq and Baghdad.