FACTBOX: Iraqi army raids Sadr City, cleric's stronghold

BAGHDAD (Reuters) - The Iraqi army launched an operation on Tuesday to take control of Baghdad's Sadr City slum, political and military stronghold of anti-American Shi'ite cleric Moqtada al-Sadr.

Here are five facts on the sprawling area of eastern Baghdad.

* Iraqi security forces and the U.S. military rarely venture into Sadr City. While they have clashed with Sadr's Mehdi Army militiamen there, they have not had a permanent presence in the densely populated district.

* Shi'ite Sadr City is one of Baghdad's poorest districts. Its population of more than 2 million suffers from poor services and high unemployment. Raw sewage and fetid piles of garbage are a common site along its dusty roads and alleyways.

* The main stronghold of Sadr's feared Mehdi Army militia, it has also been the launch pad for rocket and mortar attacks on the Green Zone government and diplomatic compound on the western bank of the Tigris River.

* It was known as Saddam City for decades in honor of former Iraqi President Saddam Hussein. After the U.S. invasion toppled him in 2003, it was renamed Sadr City after Moqtada's father, a revered cleric who was assassinated along with two of his sons on order of Saddam in 1999.

* Mehdi Army militants have been battling U.S. and Iraqi forces in Sadr City over the past seven weeks, since a military offensive against the militia in the southern oil port of Basra sparked violence in the capital and other cities. A truce was declared earlier this month, but skirmishes have continued.

(Writing by Michael Georgy; Editing by Ross Colvin)