Updated

More than 600 Mahdi Army militants — who fight in the name of Shiite cleric Moqtada al-Sadr — were detained by U.S. and Iraqi forces, including key Shiite militia leaders and Sunni insurgents, the U.S. military reported.

U.S. and Iraqi forces captured 16 Shiite militia leaders and 33 key Sunni insurgents in the past 45 days, the military said Monday in a rare statement that singled out the feared Mahdi Army of a radical Shiite cleric.

The military said the recent detentions were in addition to six other Mahdi Army leaders who have been captured since the start of October, and it added that more than 600 Mahdi Army members were in jail awaiting prosecution by the Iraqi government.

The military said 52 operations since Dec. 8 targeted the Mahdi Army, which has been blamed for much of the recent sectarian violence in the capital, while 42 focused on Sunni extremists in the same time period.

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The information was released in a statement as U.S. and Iraqi forces prepared a massive security operation that Shiite Prime Minister Nouri al-Maliki has promised show no favoritism to either Sunnis or Shiites. He was sharply criticized after past operations to clamp off violence in the capital failed when he intervened on behalf of his fellow Shiites.

Joint U.S.-Iraqi security forces detained 16 high-level members of the Mahdi Army and killed one of the group's commanders in the 45-day period, the statement said, adding that five of the individuals were commanders in the militia's Baghdad stronghold of Sadr City.

On Friday, U.S. and Iraqi forces captured senior al-Sadr aide Abdul-Hadi al-Darraji and killed his bodyguard in a raid on a mosque complex in Baghdad. The U.S. military said it had captured a "high-level, illegal armed group leader" whom it did not name, but al-Sadr's office said al-Darraji, the media director for the cleric's political movement, had been detained and demanded his immediate release.

"The detainees were responsible for attacks against the government of Iraq, Iraqi citizens, and CF (coalition forces)," the statement said. "Criminal activities by these individuals propagated instability within Iraq, and their removal from the social structure is a critical start to providing the Iraqi populace with a safe and stable environment."

The military said it had captured 33 Sunni insurgent cell leaders who were responsible for help bringing in foreign fighters, facilitate car bombs and propaganda operations in Baghdad over the past 45 days.

The United Nations said sectarian violence killed 34,452 civilians in Iraqi last year.

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